diff --git a/src/vs/platform/remote/common/tunnel.ts b/src/vs/platform/remote/common/tunnel.ts
index eea0aacc10a..b409a1d9b62 100644
--- a/src/vs/platform/remote/common/tunnel.ts
+++ b/src/vs/platform/remote/common/tunnel.ts
@@ -17,7 +17,7 @@ export interface RemoteTunnel {
 	readonly tunnelRemoteHost: string;
 	readonly tunnelLocalPort?: number;
 	readonly localAddress: string;
-	dispose(silent?: boolean): void;
+	dispose(silent?: boolean): Promise<void>;
 }
 
 export interface TunnelOptions {
@@ -119,10 +119,10 @@ export abstract class AbstractTunnelService implements ITunnelService {
 		});
 	}
 
-	dispose(): void {
+	async dispose(): Promise<void> {
 		for (const portMap of this._tunnels.values()) {
 			for (const { value } of portMap.values()) {
-				value.then(tunnel => tunnel?.dispose());
+				await value.then(tunnel => tunnel?.dispose());
 			}
 			portMap.clear();
 		}
@@ -163,13 +163,13 @@ export abstract class AbstractTunnelService implements ITunnelService {
 			tunnelRemoteHost: tunnel.tunnelRemoteHost,
 			tunnelLocalPort: tunnel.tunnelLocalPort,
 			localAddress: tunnel.localAddress,
-			dispose: () => {
+			dispose: async () => {
 				const existingHost = this._tunnels.get(tunnel.tunnelRemoteHost);
 				if (existingHost) {
 					const existing = existingHost.get(tunnel.tunnelRemotePort);
 					if (existing) {
 						existing.refcount--;
-						this.tryDisposeTunnel(tunnel.tunnelRemoteHost, tunnel.tunnelRemotePort, existing);
+						await this.tryDisposeTunnel(tunnel.tunnelRemoteHost, tunnel.tunnelRemotePort, existing);
 					}
 				}
 			}
@@ -178,9 +178,9 @@ export abstract class AbstractTunnelService implements ITunnelService {
 
 	private async tryDisposeTunnel(remoteHost: string, remotePort: number, tunnel: { refcount: number, readonly value: Promise<RemoteTunnel | undefined> }): Promise<void> {
 		if (tunnel.refcount <= 0) {
-			const disposePromise: Promise<void> = tunnel.value.then(tunnel => {
+			const disposePromise: Promise<void> = tunnel.value.then(async (tunnel) => {
 				if (tunnel) {
-					tunnel.dispose(true);
+					await tunnel.dispose(true);
 					this._onTunnelClosed.fire({ host: tunnel.tunnelRemoteHost, port: tunnel.tunnelRemotePort });
 				}
 			});
diff --git a/src/vs/platform/remote/node/tunnelService.ts b/src/vs/platform/remote/node/tunnelService.ts
index e73c5752952..b48b54838d0 100644
--- a/src/vs/platform/remote/node/tunnelService.ts
+++ b/src/vs/platform/remote/node/tunnelService.ts
@@ -57,7 +57,7 @@ class NodeRemoteTunnel extends Disposable implements RemoteTunnel {
 		this.tunnelRemoteHost = tunnelRemoteHost;
 	}
 
-	public dispose(): void {
+	public async dispose(): Promise<void> {
 		super.dispose();
 		this._server.removeListener('listening', this._listeningListener);
 		this._server.removeListener('connection', this._connectionListener);
diff --git a/src/vs/platform/webview/common/webviewPortMapping.ts b/src/vs/platform/webview/common/webviewPortMapping.ts
index 8809d667143..4e9c229762f 100644
--- a/src/vs/platform/webview/common/webviewPortMapping.ts
+++ b/src/vs/platform/webview/common/webviewPortMapping.ts
@@ -60,9 +60,9 @@ export class WebviewPortMappingManager implements IDisposable {
 		return undefined;
 	}
 
-	dispose() {
+	async dispose() {
 		for (const tunnel of this._tunnels.values()) {
-			tunnel.dispose();
+			await tunnel.dispose();
 		}
 		this._tunnels.clear();
 	}
diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 6ff3a5d563c..7a8667537a3 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -189,7 +189,7 @@ declare module 'vscode' {
 	export interface Tunnel extends TunnelDescription {
 		// Implementers of Tunnel should fire onDidDispose when dispose is called.
 		onDidDispose: Event<void>;
-		dispose(): void;
+		dispose(): void | Thenable<void>;
 	}
 
 	/**
diff --git a/src/vs/workbench/api/browser/mainThreadTunnelService.ts b/src/vs/workbench/api/browser/mainThreadTunnelService.ts
index 8261133728d..97e31283b67 100644
--- a/src/vs/workbench/api/browser/mainThreadTunnelService.ts
+++ b/src/vs/workbench/api/browser/mainThreadTunnelService.ts
@@ -66,8 +66,8 @@ export class MainThreadTunnelService extends Disposable implements MainThreadTun
 							tunnelRemoteHost: tunnel.remoteAddress.host,
 							localAddress: typeof tunnel.localAddress === 'string' ? tunnel.localAddress : makeAddress(tunnel.localAddress.host, tunnel.localAddress.port),
 							tunnelLocalPort: typeof tunnel.localAddress !== 'string' ? tunnel.localAddress.port : undefined,
-							dispose: (silent?: boolean) => {
-								this._proxy.$closeTunnel({ host: tunnel.remoteAddress.host, port: tunnel.remoteAddress.port }, silent);
+							dispose: async (silent?: boolean) => {
+								return this._proxy.$closeTunnel({ host: tunnel.remoteAddress.host, port: tunnel.remoteAddress.port }, silent);
 							}
 						};
 					});
diff --git a/src/vs/workbench/api/node/extHostTunnelService.ts b/src/vs/workbench/api/node/extHostTunnelService.ts
index 035217d4efb..2cd5c9ecc0e 100644
--- a/src/vs/workbench/api/node/extHostTunnelService.ts
+++ b/src/vs/workbench/api/node/extHostTunnelService.ts
@@ -30,11 +30,11 @@ class ExtensionTunnel implements vscode.Tunnel {
 	constructor(
 		public readonly remoteAddress: { port: number, host: string },
 		public readonly localAddress: { port: number, host: string } | string,
-		private readonly _dispose: () => void) { }
+		private readonly _dispose: () => Promise<void>) { }
 
-	dispose(): void {
+	dispose(): Promise<void> {
 		this._onDispose.fire();
-		this._dispose();
+		return this._dispose();
 	}
 }
 
@@ -212,7 +212,7 @@ export class ExtHostTunnelService extends Disposable implements IExtHostTunnelSe
 				if (silent) {
 					hostMap.get(remote.port)!.disposeListener.dispose();
 				}
-				hostMap.get(remote.port)!.tunnel.dispose();
+				await hostMap.get(remote.port)!.tunnel.dispose();
 				hostMap.delete(remote.port);
 			}
 		}
diff --git a/src/vs/workbench/contrib/remote/common/tunnelFactory.ts b/src/vs/workbench/contrib/remote/common/tunnelFactory.ts
index 6da6a274562..b3c0f17c8b4 100644
--- a/src/vs/workbench/contrib/remote/common/tunnelFactory.ts
+++ b/src/vs/workbench/contrib/remote/common/tunnelFactory.ts
@@ -36,7 +36,7 @@ export class TunnelFactoryContribution extends Disposable implements IWorkbenchC
 								// The tunnel factory may give us an inaccessible local address.
 								// To make sure this doesn't happen, resolve the uri immediately.
 								localAddress: (await openerService.resolveExternalUri(URI.parse(localAddress))).resolved.toString(),
-								dispose: tunnel.dispose
+								dispose: async () => { await tunnel.dispose; }
 							};
 							resolve(remoteTunnel);
 						});
diff --git a/src/vs/workbench/workbench.web.api.ts b/src/vs/workbench/workbench.web.api.ts
index f009cb06cc2..53e3c80ca24 100644
--- a/src/vs/workbench/workbench.web.api.ts
+++ b/src/vs/workbench/workbench.web.api.ts
@@ -73,7 +73,7 @@ export interface TunnelCreationOptions {
 	elevationRequired?: boolean;
 }
 
-interface ITunnel extends IDisposable {
+interface ITunnel {
 	remoteAddress: { port: number, host: string };
 
 	/**
@@ -85,6 +85,8 @@ interface ITunnel extends IDisposable {
 	 * Implementers of Tunnel should fire onDidDispose when dispose is called.
 	 */
 	onDidDispose: Event<void>;
+
+	dispose(): Promise<void> | void;
 }
 
 interface IShowPortCandidate {