diff --git a/Package.swift b/Package.swift
index e95ec57..9560b0e 100644
--- a/Package.swift
+++ b/Package.swift
@@ -155,7 +155,8 @@ var targets: [PackageDescription.Target] = [
         name: "NIONFS3",
         dependencies: [
             .product(name: "NIOCore", package: "swift-nio")
-        ]
+        ],
+        swiftSettings: strictConcurrencySettings
     ),
     .testTarget(
         name: "NIONFS3Tests",
@@ -164,7 +165,8 @@ var targets: [PackageDescription.Target] = [
             .product(name: "NIOCore", package: "swift-nio"),
             .product(name: "NIOEmbedded", package: "swift-nio"),
             .product(name: "NIOTestUtils", package: "swift-nio"),
-        ]
+        ],
+        swiftSettings: strictConcurrencySettings
     ),
     .target(
         name: "NIOHTTPTypes",
diff --git a/Sources/NIONFS3/NFSCallDecoder.swift b/Sources/NIONFS3/NFSCallDecoder.swift
index ba9dbab..dc347c7 100644
--- a/Sources/NIONFS3/NFSCallDecoder.swift
+++ b/Sources/NIONFS3/NFSCallDecoder.swift
@@ -14,7 +14,7 @@
 
 import NIOCore
 
-public struct NFS3CallDecoder: NIOSingleStepByteToMessageDecoder {
+public struct NFS3CallDecoder: NIOSingleStepByteToMessageDecoder, Sendable {
     public typealias InboundOut = RPCNFS3Call
 
     public init() {}
diff --git a/Sources/NIONFS3/NFSCallEncoder.swift b/Sources/NIONFS3/NFSCallEncoder.swift
index 6867a8a..c10ba51 100644
--- a/Sources/NIONFS3/NFSCallEncoder.swift
+++ b/Sources/NIONFS3/NFSCallEncoder.swift
@@ -14,7 +14,7 @@
 
 import NIOCore
 
-public struct NFS3CallEncoder: MessageToByteEncoder {
+public struct NFS3CallEncoder: MessageToByteEncoder, Sendable {
     public typealias OutboundIn = RPCNFS3Call
 
     public init() {}
diff --git a/Sources/NIONFS3/NFSFileSystem.swift b/Sources/NIONFS3/NFSFileSystem.swift
index 67a10c9..e12c5e5 100644
--- a/Sources/NIONFS3/NFSFileSystem.swift
+++ b/Sources/NIONFS3/NFSFileSystem.swift
@@ -14,7 +14,11 @@
 
 import NIOCore
 
-public protocol NFS3FileSystemNoAuth {
+@preconcurrency
+public protocol NFS3FileSystemNoAuth: Sendable {
+    // Must be Sendable; there are extensions which take an event loop and call these functions
+    // on that event loop.
+
     func mount(_ call: MountCallMount, promise: EventLoopPromise<MountReplyMount>)
     func unmount(_ call: MountCallUnmount, promise: EventLoopPromise<MountReplyUnmount>)
     func getattr(_ call: NFS3CallGetAttr, promise: EventLoopPromise<NFS3ReplyGetAttr>)
diff --git a/Sources/NIONFS3/NFSFileSystemHandler.swift b/Sources/NIONFS3/NFSFileSystemHandler.swift
index c49ad0d..637bbe4 100644
--- a/Sources/NIONFS3/NFSFileSystemHandler.swift
+++ b/Sources/NIONFS3/NFSFileSystemHandler.swift
@@ -22,7 +22,7 @@ import NIOCore
 /// `NFS3FileSystemNoAuthHandler` ignores any [SUN RPC](https://datatracker.ietf.org/doc/html/rfc5531) credentials /
 /// verifiers and always replies with `AUTH_NONE`. If you need to implement access control via UNIX user/group, this
 /// handler will not be enough. It assumes that every call is allowed. Please note that this is not a security risk
-/// because NFS3 tranditionally just trusts the UNIX uid/gid that the client provided. So there's no security value
+/// because NFS3 traditionally just trusts the UNIX uid/gid that the client provided. So there's no security value
 /// added by verifying them. However, the client may rely on the server to check the UNIX permissions (whilst trusting
 /// the uid/gid) which cannot be done with this handler.
 public final class NFS3FileSystemNoAuthHandler<FS: NFS3FileSystemNoAuth>: ChannelDuplexHandler, NFS3FileSystemResponder
@@ -118,3 +118,6 @@ public final class NFS3FileSystemNoAuthHandler<FS: NFS3FileSystemNoAuth>: Channe
         context.fireErrorCaught(error)
     }
 }
+
+@available(*, unavailable)
+extension NFS3FileSystemNoAuthHandler: Sendable {}
diff --git a/Sources/NIONFS3/NFSFileSystemInvoker.swift b/Sources/NIONFS3/NFSFileSystemInvoker.swift
index c117efa..55030c9 100644
--- a/Sources/NIONFS3/NFSFileSystemInvoker.swift
+++ b/Sources/NIONFS3/NFSFileSystemInvoker.swift
@@ -39,7 +39,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
         case .mountNull:
             self.sink.sendSuccessfulReply(.mountNull, call: callMessage)
         case .mount(let call):
-            self.fs.mount(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.mount(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.mount(reply), call: callMessage)
@@ -48,7 +48,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .unmount(let call):
-            self.fs.unmount(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.unmount(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.unmount(reply), call: callMessage)
@@ -59,7 +59,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
         case .null:
             self.sink.sendSuccessfulReply(.null, call: callMessage)
         case .getattr(let call):
-            self.fs.getattr(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.getattr(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.getattr(reply), call: callMessage)
@@ -68,7 +68,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .fsinfo(let call):
-            self.fs.fsinfo(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.fsinfo(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.fsinfo(reply), call: callMessage)
@@ -77,7 +77,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .pathconf(let call):
-            self.fs.pathconf(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.pathconf(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.pathconf(reply), call: callMessage)
@@ -86,7 +86,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .fsstat(let call):
-            self.fs.fsstat(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.fsstat(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.fsstat(reply), call: callMessage)
@@ -95,7 +95,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .access(let call):
-            self.fs.access(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.access(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.access(reply), call: callMessage)
@@ -104,7 +104,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .lookup(let call):
-            self.fs.lookup(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.lookup(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.lookup(reply), call: callMessage)
@@ -113,7 +113,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .readdirplus(let call):
-            self.fs.readdirplus(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.readdirplus(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.readdirplus(reply), call: callMessage)
@@ -122,7 +122,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .read(let call):
-            self.fs.read(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.read(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.read(reply), call: callMessage)
@@ -131,7 +131,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .readdir(let call):
-            self.fs.readdir(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.readdir(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.readdir(reply), call: callMessage)
@@ -140,7 +140,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .readlink(let call):
-            self.fs.readlink(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.readlink(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.readlink(reply), call: callMessage)
@@ -149,7 +149,7 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
                 }
             }
         case .setattr(let call):
-            self.fs.setattr(call, eventLoop: self.eventLoop).whenComplete { result in
+            self.fs.setattr(call, eventLoop: self.eventLoop).assumeIsolated().whenComplete { result in
                 switch result {
                 case .success(let reply):
                     self.sink.sendSuccessfulReply(.setattr(reply), call: callMessage)
@@ -163,3 +163,6 @@ internal struct NFS3FileSystemInvoker<FS: NFS3FileSystemNoAuth, Sink: NFS3FileSy
         }
     }
 }
+
+@available(*, unavailable)
+extension NFS3FileSystemInvoker: Sendable {}
diff --git a/Sources/NIONFS3/NFSFileSystemServerHandler.swift b/Sources/NIONFS3/NFSFileSystemServerHandler.swift
index 88c7455..c04377a 100644
--- a/Sources/NIONFS3/NFSFileSystemServerHandler.swift
+++ b/Sources/NIONFS3/NFSFileSystemServerHandler.swift
@@ -150,3 +150,6 @@ extension NFS3FileSystemServerHandler: NFS3FileSystemResponder {
         }
     }
 }
+
+@available(*, unavailable)
+extension NFS3FileSystemServerHandler: Sendable {}
diff --git a/Sources/NIONFS3/NFSReplyDecoder.swift b/Sources/NIONFS3/NFSReplyDecoder.swift
index cb98020..fd94bbe 100644
--- a/Sources/NIONFS3/NFSReplyDecoder.swift
+++ b/Sources/NIONFS3/NFSReplyDecoder.swift
@@ -67,3 +67,6 @@ public struct NFS3ReplyDecoder: WriteObservingByteToMessageDecoder {
         self.procedures[data.rpcCall.xid] = data.rpcCall.programAndProcedure
     }
 }
+
+@available(*, unavailable)
+extension NFS3ReplyDecoder: Sendable {}
diff --git a/Sources/NIONFS3/NFSReplyEncoder.swift b/Sources/NIONFS3/NFSReplyEncoder.swift
index ff1a496..42de79d 100644
--- a/Sources/NIONFS3/NFSReplyEncoder.swift
+++ b/Sources/NIONFS3/NFSReplyEncoder.swift
@@ -14,7 +14,7 @@
 
 import NIOCore
 
-public struct NFS3ReplyEncoder: MessageToByteEncoder {
+public struct NFS3ReplyEncoder: MessageToByteEncoder, Sendable {
     public typealias OutboundIn = RPCNFS3Reply
 
     public init() {}
diff --git a/Tests/NIONFS3Tests/NFS3FileSystemTests.swift b/Tests/NIONFS3Tests/NFS3FileSystemTests.swift
index 55cf29a..934993b 100644
--- a/Tests/NIONFS3Tests/NFS3FileSystemTests.swift
+++ b/Tests/NIONFS3Tests/NFS3FileSystemTests.swift
@@ -19,7 +19,7 @@ import XCTest
 
 final class NFS3FileSystemTests: XCTestCase {
     func testReadDirDefaultImplementation() throws {
-        class MyOnlyReadDirPlusFS: NFS3FileSystemNoAuth {
+        final class MyOnlyReadDirPlusFS: NFS3FileSystemNoAuth {
             func shutdown(promise: EventLoopPromise<Void>) {
                 promise.succeed(())
             }