diff --git a/Cargo.lock b/Cargo.lock
index 9eae93751..38926b1d2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2272,15 +2272,6 @@ dependencies = [
  "synstructure",
 ]
 
-[[package]]
-name = "generational-arena"
-version = "0.2.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "877e94aff08e743b651baaea359664321055749b398adff8740a7399af7796e7"
-dependencies = [
- "cfg-if",
-]
-
 [[package]]
 name = "generator"
 version = "0.7.5"
@@ -4464,7 +4455,6 @@ dependencies = [
  "flv-rs",
  "fnv",
  "futures",
- "generational-arena",
  "hashbrown 0.14.3",
  "image",
  "indexmap",
@@ -4489,6 +4479,7 @@ dependencies = [
  "scopeguard",
  "serde",
  "serde_json",
+ "slotmap",
  "smallvec",
  "swf",
  "symphonia",
@@ -4525,7 +4516,6 @@ dependencies = [
  "fontdb",
  "futures",
  "futures-lite 2.2.0",
- "generational-arena",
  "gilrs",
  "image",
  "isahc",
@@ -4536,6 +4526,7 @@ dependencies = [
  "ruffle_render",
  "ruffle_render_wgpu",
  "ruffle_video_software",
+ "slotmap",
  "sys-locale",
  "tokio",
  "tracing",
@@ -4717,8 +4708,8 @@ dependencies = [
 name = "ruffle_video"
 version = "0.1.0"
 dependencies = [
- "generational-arena",
  "ruffle_render",
+ "slotmap",
  "swf",
  "thiserror",
 ]
@@ -4728,7 +4719,6 @@ name = "ruffle_video_software"
 version = "0.1.0"
 dependencies = [
  "flate2",
- "generational-arena",
  "h263-rs",
  "h263-rs-deblock",
  "log",
@@ -4737,6 +4727,7 @@ dependencies = [
  "nihav_duck",
  "ruffle_render",
  "ruffle_video",
+ "slotmap",
  "swf",
  "thiserror",
 ]
@@ -4751,7 +4742,6 @@ dependencies = [
  "console_error_panic_hook",
  "futures",
  "futures-util",
- "generational-arena",
  "getrandom",
  "gloo-net",
  "js-sys",
@@ -4765,6 +4755,7 @@ dependencies = [
  "ruffle_web_common",
  "serde",
  "serde-wasm-bindgen",
+ "slotmap",
  "thiserror",
  "tracing",
  "tracing-log",
diff --git a/Cargo.toml b/Cargo.toml
index 60bd0a243..a6c015fa3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -51,6 +51,7 @@ wgpu = "0.19.3"
 egui = "0.26.2"
 clap = { version = "4.5.1", features = ["derive"] }
 anyhow = "1.0"
+slotmap = "1.0.7"
 
 [workspace.lints.rust]
 # Clippy nightly often adds new/buggy lints that we want to ignore.
diff --git a/core/Cargo.toml b/core/Cargo.toml
index db6fc90fb..04724aed8 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -17,7 +17,7 @@ bitstream-io = "2.2.0"
 flate2 = "1.0.28"
 fnv = "1.0.7"
 gc-arena = { package = "ruffle_gc_arena", path = "../ruffle_gc_arena" }
-generational-arena = "0.2.9"
+slotmap = { workspace = true }
 indexmap = "2.2.5"
 tracing = { workspace = true }
 ruffle_render = { path = "../render", features = ["tessellator"] }
diff --git a/core/src/backend/audio.rs b/core/src/backend/audio.rs
index 8a913887f..ba5364cf5 100644
--- a/core/src/backend/audio.rs
+++ b/core/src/backend/audio.rs
@@ -7,7 +7,7 @@ use crate::{
 };
 use downcast_rs::Downcast;
 use gc_arena::Collect;
-use generational_arena::{Arena, Index};
+use slotmap::{DefaultKey, Key, SlotMap};
 
 #[cfg(feature = "audio")]
 pub mod decoders;
@@ -35,8 +35,8 @@ mod decoders {
 use thiserror::Error;
 use web_time::Duration;
 
-pub type SoundHandle = Index;
-pub type SoundInstanceHandle = Index;
+pub type SoundHandle = DefaultKey;
+pub type SoundInstanceHandle = DefaultKey;
 pub type DecodeError = decoders::Error;
 
 #[derive(Eq, PartialEq, Clone, Copy, Debug)]
@@ -205,14 +205,14 @@ struct NullSound {
 
 /// Audio backend that ignores all audio.
 pub struct NullAudioBackend {
-    sounds: Arena<NullSound>,
+    sounds: SlotMap<SoundHandle, NullSound>,
     volume: f32,
 }
 
 impl NullAudioBackend {
     pub fn new() -> NullAudioBackend {
         NullAudioBackend {
-            sounds: Arena::new(),
+            sounds: SlotMap::new(),
             volume: 1.0,
         }
     }
@@ -259,7 +259,7 @@ impl AudioBackend for NullAudioBackend {
         _sound: SoundHandle,
         _sound_info: &swf::SoundInfo,
     ) -> Result<SoundInstanceHandle, DecodeError> {
-        Ok(SoundInstanceHandle::from_raw_parts(0, 0))
+        Ok(SoundInstanceHandle::null())
     }
 
     fn start_stream(
@@ -267,7 +267,7 @@ impl AudioBackend for NullAudioBackend {
         _clip_data: crate::tag_utils::SwfSlice,
         _handle: &swf::SoundStreamHead,
     ) -> Result<SoundInstanceHandle, DecodeError> {
-        Ok(SoundInstanceHandle::from_raw_parts(0, 0))
+        Ok(SoundInstanceHandle::null())
     }
 
     fn start_substream(
@@ -275,7 +275,7 @@ impl AudioBackend for NullAudioBackend {
         _stream_data: Substream,
         _handle: &SoundStreamInfo,
     ) -> Result<SoundInstanceHandle, DecodeError> {
-        Ok(SoundInstanceHandle::from_raw_parts(0, 0))
+        Ok(SoundInstanceHandle::null())
     }
 
     fn stop_sound(&mut self, _sound: SoundInstanceHandle) {}
diff --git a/core/src/backend/audio/mixer.rs b/core/src/backend/audio/mixer.rs
index 081865fe5..ab6d548c6 100644
--- a/core/src/backend/audio/mixer.rs
+++ b/core/src/backend/audio/mixer.rs
@@ -3,7 +3,7 @@ use super::{SoundHandle, SoundInstanceHandle, SoundStreamInfo, SoundTransform};
 use crate::backend::audio::{DecodeError, RegisterError};
 use crate::buffer::Substream;
 use crate::tag_utils::SwfSlice;
-use generational_arena::Arena;
+use slotmap::SlotMap;
 use std::io::Cursor;
 use std::sync::{Arc, Mutex, RwLock};
 use swf::AudioCompression;
@@ -54,10 +54,10 @@ impl CircBuf {
 // all sounds and mix the audio into an output buffer audio stream.
 pub struct AudioMixer {
     /// The currently registered sounds.
-    sounds: Arena<Sound>,
+    sounds: SlotMap<SoundHandle, Sound>,
 
     /// The list of actively playing sound instances.
-    sound_instances: Arc<Mutex<Arena<SoundInstance>>>,
+    sound_instances: Arc<Mutex<SlotMap<SoundInstanceHandle, SoundInstance>>>,
 
     /// The master volume of the audio from [0.0, 1.0].
     volume: Arc<RwLock<f32>>,
@@ -239,8 +239,8 @@ impl AudioMixer {
     /// Creates a new `AudioMixer` with the given number of channels and sample rate.
     pub fn new(num_output_channels: u8, output_sample_rate: u32) -> Self {
         Self {
-            sounds: Arena::new(),
-            sound_instances: Arc::new(Mutex::new(Arena::new())),
+            sounds: SlotMap::new(),
+            sound_instances: Arc::new(Mutex::new(SlotMap::new())),
             volume: Arc::new(RwLock::new(1.0)),
             num_output_channels,
             output_sample_rate,
@@ -428,7 +428,7 @@ impl AudioMixer {
     /// Refill the output buffer by stepping through all active sounds
     /// and mixing in their output.
     fn mix_audio<'a, T>(
-        sound_instances: &mut Arena<SoundInstance>,
+        sound_instances: &mut SlotMap<SoundInstanceHandle, SoundInstance>,
         volume: f32,
         num_channels: u8,
         mut output_buffer: &mut [T],
@@ -724,7 +724,7 @@ impl AudioMixer {
 /// to perform audio mixing on a different thread.
 pub struct AudioMixerProxy {
     /// The list of actively playing sound instances.
-    sound_instances: Arc<Mutex<Arena<SoundInstance>>>,
+    sound_instances: Arc<Mutex<SlotMap<SoundInstanceHandle, SoundInstance>>>,
 
     /// The master volume of the audio from [0.0, 1.0].
     volume: Arc<RwLock<f32>>,
diff --git a/core/src/loader.rs b/core/src/loader.rs
index 9e92f0579..13bb04f47 100644
--- a/core/src/loader.rs
+++ b/core/src/loader.rs
@@ -32,8 +32,8 @@ use crate::vminterface::Instantiator;
 use crate::{avm2_stub_method, avm2_stub_method_context};
 use encoding_rs::UTF_8;
 use gc_arena::{Collect, GcCell};
-use generational_arena::{Arena, Index};
 use ruffle_render::utils::{determine_jpeg_tag_format, JpegTagFormat};
+use slotmap::{DefaultKey, SlotMap};
 use std::borrow::Borrow;
 use std::fmt;
 use std::sync::{Arc, Mutex, Weak};
@@ -42,7 +42,7 @@ use swf::read::{extract_swz, read_compression_type};
 use thiserror::Error;
 use url::{form_urlencoded, ParseError, Url};
 
-pub type Handle = Index;
+pub type Handle = DefaultKey;
 
 /// The depth of AVM1 movies that AVM2 loads.
 const LOADER_INSERTED_AVM1_DEPTH: i32 = -0xF000;
@@ -224,7 +224,7 @@ impl From<crate::avm1::Error<'_>> for Error {
 }
 
 /// Holds all in-progress loads for the player.
-pub struct LoadManager<'gc>(Arena<Loader<'gc>>);
+pub struct LoadManager<'gc>(SlotMap<Handle, Loader<'gc>>);
 
 unsafe impl<'gc> Collect for LoadManager<'gc> {
     fn trace(&self, cc: &gc_arena::Collection) {
@@ -237,7 +237,7 @@ unsafe impl<'gc> Collect for LoadManager<'gc> {
 impl<'gc> LoadManager<'gc> {
     /// Construct a new `LoadManager`.
     pub fn new() -> Self {
-        Self(Arena::new())
+        Self(SlotMap::new())
     }
 
     /// Add a new loader to the `LoadManager`.
@@ -355,15 +355,24 @@ impl<'gc> LoadManager<'gc> {
     ///
     /// This also removes all movie loaders that have completed.
     pub fn movie_clip_on_load(&mut self, queue: &mut ActionQueue<'gc>) {
-        let mut invalidated_loaders = vec![];
+        // FIXME: This relies on the iteration order of the slotmap, which
+        // is not defined. The container should be replaced with something
+        // that preserves insertion order, such as `LinkedHashMap` -
+        // unfortunately that doesn't provide automatic key generation.
+        let mut loaders: Vec<_> = self.0.keys().collect();
+        // `SlotMap` doesn't provide reverse iteration, so reversing afterwards.
+        loaders.reverse();
 
-        for (index, loader) in self.0.iter_mut().rev() {
-            if loader.movie_clip_loaded(queue) {
-                invalidated_loaders.push(index);
-            }
-        }
+        // Removing the keys from `loaders` whose movie hasn't loaded yet.
+        loaders.retain(|handle| {
+            self.0
+                .get_mut(*handle)
+                .expect("valid key")
+                .movie_clip_loaded(queue)
+        });
 
-        for index in invalidated_loaders {
+        // Cleaning up the loaders that are done.
+        for index in loaders {
             self.0.remove(index);
         }
     }
@@ -1692,7 +1701,7 @@ impl<'gc> Loader<'gc> {
     }
 
     /// Report a movie loader start event to script code.
-    fn movie_loader_start(handle: Index, uc: &mut UpdateContext<'_, 'gc>) -> Result<(), Error> {
+    fn movie_loader_start(handle: Handle, uc: &mut UpdateContext<'_, 'gc>) -> Result<(), Error> {
         let me = uc.load_manager.get_loader_mut(handle);
         if me.is_none() {
             return Err(Error::Cancelled);
@@ -2080,7 +2089,7 @@ impl<'gc> Loader<'gc> {
     ///
     /// The current and total length are always reported as compressed lengths.
     fn movie_loader_progress(
-        handle: Index,
+        handle: Handle,
         uc: &mut UpdateContext<'_, 'gc>,
         cur_len: usize,
         total_len: usize,
@@ -2146,7 +2155,7 @@ impl<'gc> Loader<'gc> {
 
     /// Report a movie loader completion to script code.
     fn movie_loader_complete(
-        handle: Index,
+        handle: Handle,
         uc: &mut UpdateContext<'_, 'gc>,
         dobj: Option<DisplayObject<'gc>>,
         status: u16,
@@ -2315,7 +2324,7 @@ impl<'gc> Loader<'gc> {
     /// This is an associated function because we cannot borrow both the update
     /// context and one of it's loaders.
     fn movie_loader_error(
-        handle: Index,
+        handle: Handle,
         uc: &mut UpdateContext<'_, 'gc>,
         msg: AvmString<'gc>,
         status: u16,
diff --git a/core/src/local_connection.rs b/core/src/local_connection.rs
index 1f936b85b..b1bffb7f4 100644
--- a/core/src/local_connection.rs
+++ b/core/src/local_connection.rs
@@ -2,9 +2,9 @@ use crate::avm1::Object as Avm1Object;
 use crate::avm2::object::LocalConnectionObject;
 use crate::string::AvmString;
 use gc_arena::Collect;
-use generational_arena::{Arena, Index};
+use slotmap::{DefaultKey, SlotMap};
 
-pub type LocalConnectionHandle = Index;
+pub type LocalConnectionHandle = DefaultKey;
 
 #[derive(Collect)]
 #[collect(no_drop)]
@@ -41,7 +41,7 @@ impl<'gc> LocalConnection<'gc> {
 
 /// Manages the collection of local connections.
 pub struct LocalConnections<'gc> {
-    connections: Arena<LocalConnection<'gc>>,
+    connections: SlotMap<LocalConnectionHandle, LocalConnection<'gc>>,
 }
 
 unsafe impl<'gc> Collect for LocalConnections<'gc> {
@@ -55,7 +55,7 @@ unsafe impl<'gc> Collect for LocalConnections<'gc> {
 impl<'gc> LocalConnections<'gc> {
     pub fn empty() -> Self {
         Self {
-            connections: Arena::new(),
+            connections: SlotMap::new(),
         }
     }
 
diff --git a/core/src/net_connection.rs b/core/src/net_connection.rs
index 735175158..e2c648bc6 100644
--- a/core/src/net_connection.rs
+++ b/core/src/net_connection.rs
@@ -10,12 +10,12 @@ use crate::Player;
 use flash_lso::packet::{Header, Message, Packet};
 use flash_lso::types::{AMFVersion, Value as AmfValue};
 use gc_arena::{Collect, DynamicRoot, Rootable};
-use generational_arena::{Arena, Index};
+use slotmap::{DefaultKey, SlotMap};
 use std::fmt::{Debug, Formatter};
 use std::rc::Rc;
 use std::sync::{Mutex, Weak};
 
-pub type NetConnectionHandle = Index;
+pub type NetConnectionHandle = DefaultKey;
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub enum ResponderCallback {
@@ -76,7 +76,7 @@ impl<'gc> From<Avm2NetConnectionObject<'gc>> for NetConnectionObject<'gc> {
 
 /// Manages the collection of NetConnections.
 pub struct NetConnections<'gc> {
-    connections: Arena<NetConnection<'gc>>,
+    connections: SlotMap<NetConnectionHandle, NetConnection<'gc>>,
 }
 
 unsafe impl<'gc> Collect for NetConnections<'gc> {
@@ -90,7 +90,7 @@ unsafe impl<'gc> Collect for NetConnections<'gc> {
 impl<'gc> Default for NetConnections<'gc> {
     fn default() -> Self {
         Self {
-            connections: Arena::new(),
+            connections: SlotMap::new(),
         }
     }
 }
diff --git a/core/src/socket.rs b/core/src/socket.rs
index 3ba328fbc..1a91446a2 100644
--- a/core/src/socket.rs
+++ b/core/src/socket.rs
@@ -13,13 +13,13 @@ use crate::{
 };
 use async_channel::{unbounded, Receiver, Sender as AsyncSender, Sender};
 use gc_arena::Collect;
-use generational_arena::{Arena, Index};
+use slotmap::{DefaultKey, SlotMap};
 use std::{
     cell::{Cell, RefCell},
     time::Duration,
 };
 
-pub type SocketHandle = Index;
+pub type SocketHandle = DefaultKey;
 
 #[derive(Copy, Clone, Collect)]
 #[collect(no_drop)]
@@ -62,7 +62,7 @@ pub enum SocketAction {
 
 /// Manages the collection of Sockets.
 pub struct Sockets<'gc> {
-    sockets: Arena<Socket<'gc>>,
+    sockets: SlotMap<SocketHandle, Socket<'gc>>,
 
     receiver: Receiver<SocketAction>,
     sender: Sender<SocketAction>,
@@ -81,7 +81,7 @@ impl<'gc> Sockets<'gc> {
         let (sender, receiver) = unbounded();
 
         Self {
-            sockets: Arena::new(),
+            sockets: SlotMap::new(),
             receiver,
             sender,
         }
diff --git a/desktop/Cargo.toml b/desktop/Cargo.toml
index e9000e83b..3e0fb2a0c 100644
--- a/desktop/Cargo.toml
+++ b/desktop/Cargo.toml
@@ -25,7 +25,7 @@ ruffle_render_wgpu = { path = "../render/wgpu", features = ["clap"] }
 ruffle_video_software = { path = "../video/software", optional = true }
 tracing = { workspace = true}
 tracing-subscriber = { workspace = true }
-generational-arena = "0.2.9"
+slotmap = { workspace = true }
 winit = "0.29.13"
 webbrowser = "0.8.12"
 url = "2.5.0"
diff --git a/desktop/src/backends/navigator.rs b/desktop/src/backends/navigator.rs
index 64a3d0e50..bf099c498 100644
--- a/desktop/src/backends/navigator.rs
+++ b/desktop/src/backends/navigator.rs
@@ -677,7 +677,7 @@ mod tests {
 
     macro_rules! dummy_handle {
         () => {
-            SocketHandle::from_raw_parts(4, 2)
+            SocketHandle::default()
         };
     }
 
diff --git a/desktop/src/executor.rs b/desktop/src/executor.rs
index 2b3d62ce1..f8c892d6f 100644
--- a/desktop/src/executor.rs
+++ b/desktop/src/executor.rs
@@ -3,9 +3,9 @@
 use crate::custom_event::RuffleEvent;
 use crate::task::Task;
 use async_channel::{unbounded, Receiver, Sender};
-use generational_arena::{Arena, Index};
 use ruffle_core::backend::navigator::OwnedFuture;
 use ruffle_core::loader::Error;
+use slotmap::{DefaultKey, SlotMap};
 use std::sync::{Arc, Mutex, Weak};
 use std::task::{Context, Poll, RawWaker, RawWakerVTable, Waker};
 use winit::event_loop::EventLoopProxy;
@@ -17,7 +17,7 @@ use winit::event_loop::EventLoopProxy;
 #[derive(Clone)]
 struct TaskHandle {
     /// The arena handle for a given task.
-    handle: Index,
+    handle: DefaultKey,
 
     /// The executor the task belongs to.
     ///
@@ -28,7 +28,7 @@ struct TaskHandle {
 
 impl TaskHandle {
     /// Construct a handle to a given task.
-    fn for_task(task: Index, executor: Weak<Mutex<WinitAsyncExecutor>>) -> Self {
+    fn for_task(task: DefaultKey, executor: Weak<Mutex<WinitAsyncExecutor>>) -> Self {
         Self {
             handle: task,
             executor,
@@ -128,7 +128,7 @@ impl TaskHandle {
 
 pub struct WinitAsyncExecutor {
     /// List of all spawned tasks.
-    task_queue: Arena<Task>,
+    task_queue: SlotMap<DefaultKey, Task>,
 
     /// Source of tasks sent to us by the `NavigatorBackend`.
     channel: Receiver<OwnedFuture<(), Error>>,
@@ -152,7 +152,7 @@ impl WinitAsyncExecutor {
         let (send, recv) = unbounded();
         let new_self = Arc::new_cyclic(|self_ref| {
             Mutex::new(Self {
-                task_queue: Arena::new(),
+                task_queue: SlotMap::new(),
                 channel: recv,
                 self_ref: self_ref.clone(),
                 event_loop: event_loop.clone(),
@@ -200,7 +200,7 @@ impl WinitAsyncExecutor {
     }
 
     /// Mark a task as ready to proceed.
-    fn wake(&mut self, task: Index) {
+    fn wake(&mut self, task: DefaultKey) {
         if let Some(task) = self.task_queue.get_mut(task) {
             if !task.is_completed() {
                 task.set_ready();
diff --git a/video/Cargo.toml b/video/Cargo.toml
index ba0e0ab23..8020af5c6 100644
--- a/video/Cargo.toml
+++ b/video/Cargo.toml
@@ -13,7 +13,7 @@ workspace = true
 [dependencies]
 swf = { path = "../swf" }
 ruffle_render = { path = "../render" }
-generational-arena = "0.2.9"
+slotmap = { workspace = true }
 thiserror = "1.0"
 
 [features]
diff --git a/video/software/Cargo.toml b/video/software/Cargo.toml
index f698b9985..e0c2d65da 100644
--- a/video/software/Cargo.toml
+++ b/video/software/Cargo.toml
@@ -14,7 +14,7 @@ workspace = true
 ruffle_render = { path = "../../render" }
 ruffle_video = { path = ".." }
 swf = { path = "../../swf" }
-generational-arena = "0.2.9"
+slotmap = { workspace = true }
 thiserror = "1.0"
 flate2 = "1.0.28"
 log = "0.4"
diff --git a/video/software/src/backend.rs b/video/software/src/backend.rs
index 3f59bcdf3..d5d8b3ba3 100644
--- a/video/software/src/backend.rs
+++ b/video/software/src/backend.rs
@@ -1,17 +1,17 @@
 use crate::decoder::VideoDecoder;
-use generational_arena::Arena;
 use ruffle_render::backend::RenderBackend;
 use ruffle_render::bitmap::{BitmapHandle, BitmapInfo, PixelRegion};
 use ruffle_video::backend::VideoBackend;
 use ruffle_video::error::Error;
 use ruffle_video::frame::{EncodedFrame, FrameDependency};
 use ruffle_video::VideoStreamHandle;
+use slotmap::SlotMap;
 use swf::{VideoCodec, VideoDeblocking};
 
 /// Software video backend that proxies to CPU-only codec implementations that
 /// ship with Ruffle.
 pub struct SoftwareVideoBackend {
-    streams: Arena<VideoStream>,
+    streams: SlotMap<VideoStreamHandle, VideoStream>,
 }
 
 impl Default for SoftwareVideoBackend {
@@ -23,7 +23,7 @@ impl Default for SoftwareVideoBackend {
 impl SoftwareVideoBackend {
     pub fn new() -> Self {
         Self {
-            streams: Arena::new(),
+            streams: SlotMap::new(),
         }
     }
 }
diff --git a/video/src/lib.rs b/video/src/lib.rs
index 3c7152fc5..fb7885fa5 100644
--- a/video/src/lib.rs
+++ b/video/src/lib.rs
@@ -1,10 +1,10 @@
 #![deny(clippy::unwrap_used)]
 
-use generational_arena::Index;
+use slotmap::DefaultKey;
 
 pub mod backend;
 pub mod error;
 pub mod frame;
 pub mod null;
 
-pub type VideoStreamHandle = Index;
+pub type VideoStreamHandle = DefaultKey;
diff --git a/video/src/null.rs b/video/src/null.rs
index 6d537f583..f51d3faed 100644
--- a/video/src/null.rs
+++ b/video/src/null.rs
@@ -2,13 +2,13 @@ use crate::backend::VideoBackend;
 use crate::error::Error;
 use crate::frame::{EncodedFrame, FrameDependency};
 use crate::VideoStreamHandle;
-use generational_arena::Arena;
 use ruffle_render::backend::RenderBackend;
 use ruffle_render::bitmap::BitmapInfo;
+use slotmap::SlotMap;
 use swf::{VideoCodec, VideoDeblocking};
 
 pub struct NullVideoBackend {
-    streams: Arena<()>,
+    streams: SlotMap<VideoStreamHandle, ()>,
 }
 
 /// Implementation of video that does not decode any video.
@@ -22,7 +22,7 @@ pub struct NullVideoBackend {
 impl NullVideoBackend {
     pub fn new() -> Self {
         Self {
-            streams: Arena::new(),
+            streams: SlotMap::new(),
         }
     }
 }
diff --git a/web/Cargo.toml b/web/Cargo.toml
index 2345548bd..25a6f6393 100644
--- a/web/Cargo.toml
+++ b/web/Cargo.toml
@@ -32,7 +32,7 @@ profiling = []
 
 [dependencies]
 console_error_panic_hook = { version = "0.1.7", optional = true }
-generational-arena = "0.2.9"
+slotmap = { workspace = true }
 js-sys = "0.3.68"
 tracing = { workspace = true, features = ["log"] }
 tracing-subscriber = { version = "0.3.18", default-features = false, features = ["registry"] }
diff --git a/web/src/lib.rs b/web/src/lib.rs
index 4c86b7e52..42d28983b 100644
--- a/web/src/lib.rs
+++ b/web/src/lib.rs
@@ -7,7 +7,6 @@ mod navigator;
 mod storage;
 mod ui;
 
-use generational_arena::{Arena, Index};
 use js_sys::{Array, Error as JsError, Function, Object, Promise, Uint8Array};
 use ruffle_core::backend::navigator::OpenURLMode;
 use ruffle_core::backend::ui::FontDefinition;
@@ -29,6 +28,7 @@ use ruffle_render::quality::StageQuality;
 use ruffle_video_software::backend::SoftwareVideoBackend;
 use ruffle_web_common::JsResult;
 use serde::{Deserialize, Serialize};
+use slotmap::{DefaultKey, SlotMap};
 use std::collections::BTreeMap;
 use std::rc::Rc;
 use std::str::FromStr;
@@ -52,7 +52,7 @@ thread_local! {
     /// We store the actual instances of the ruffle core in a static pool.
     /// This gives us a clear boundary between the JS side and Rust side, avoiding
     /// issues with lifetimes and type parameters (which cannot be exported with wasm-bindgen).
-    static INSTANCES: RefCell<Arena<RefCell<RuffleInstance>>> = RefCell::new(Arena::new());
+    static INSTANCES: RefCell<SlotMap<DefaultKey, RefCell<RuffleInstance>>> = RefCell::new(SlotMap::new());
 
     static CURRENT_CONTEXT: RefCell<Option<*mut UpdateContext<'static, 'static>>> = const { RefCell::new(None) };
 }
@@ -339,7 +339,7 @@ struct MovieMetadata {
 /// This type is exported to JS, and is used to interact with the library.
 #[wasm_bindgen]
 #[derive(Clone, Copy)]
-pub struct Ruffle(Index);
+pub struct Ruffle(DefaultKey);
 
 #[wasm_bindgen]
 impl Ruffle {