diff --git a/apps/web/src/components/features/session/create-session-form.tsx b/apps/web/src/components/features/session/create-session-form.tsx
index d32b1c0..98fac07 100644
--- a/apps/web/src/components/features/session/create-session-form.tsx
+++ b/apps/web/src/components/features/session/create-session-form.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Icon } from "../../icon";
+import { LoadingOverlay } from "../../loading-overlay";
 import {
 	createInstance,
 	startInstance,
@@ -215,6 +216,7 @@ export const CreateSessionForm = ({
 
 	return (
 		<div className={`create-session-form-wrapper ${className}`}>
+			<LoadingOverlay visible={isSubmitting} label="Creating session..." />
 			<form onSubmit={handleSubmit} className="stack create-session-form">
 				{/* Project */}
 				<div className="form-field">
diff --git a/apps/web/src/components/features/session/session-card.tsx b/apps/web/src/components/features/session/session-card.tsx
index 81856b1..274ad78 100644
--- a/apps/web/src/components/features/session/session-card.tsx
+++ b/apps/web/src/components/features/session/session-card.tsx
@@ -3,6 +3,7 @@ import type { Session } from "../../../api/sessions";
 import { Icon } from "../../icon";
 import { useMobileViewport } from "../../../hooks/use-mobile-viewport";
 import { MobileActionSheet } from "../mobile/mobile-action-sheet";
+import { LoadingOverlay } from "../../loading-overlay";
 import type { IconName } from "../../icon";
 
 export interface SessionCardProps {
@@ -14,6 +15,7 @@ export interface SessionCardProps {
 	onRecreateTunnel?: (session: Session) => void;
 	onRename?: (session: Session, newName: string) => void;
 	isBusy?: boolean;
+	busyLabel?: string;
 	tunnelHealth?: {
 		healthy: boolean;
 		container_status: string;
@@ -46,6 +48,7 @@ export function SessionCard({
 	onRecreateTunnel,
 	onRename,
 	isBusy = false,
+	busyLabel = "Working...",
 	tunnelHealth = null,
 }: SessionCardProps) {
 	const [showActionSheet, setShowActionSheet] = useState(false);
@@ -106,6 +109,7 @@ export function SessionCard({
 
 	return (
 		<article className="card session-card">
+			<LoadingOverlay visible={isBusy} label={busyLabel} />
 			<div className="session-card-content">
 				<div className="session-card-header">
 					<div className="session-card-title">
diff --git a/apps/web/src/components/features/tool/instance-list.tsx b/apps/web/src/components/features/tool/instance-list.tsx
index 7496d37..de5b878 100644
--- a/apps/web/src/components/features/tool/instance-list.tsx
+++ b/apps/web/src/components/features/tool/instance-list.tsx
@@ -1,6 +1,7 @@
 import { useCallback, useEffect, useState } from "react";
 import { useNavigate } from "react-router-dom";
 import { Icon } from "../../icon";
+import { LoadingOverlay } from "../../loading-overlay";
 import type { ToolInstance } from "../../../api/sessions";
 import {
 	deleteInstance,
@@ -60,6 +61,7 @@ export const InstanceList = ({
 
 	// Per-instance busy state for actions
 	const [busyInstanceId, setBusyInstanceId] = useState<string | null>(null);
+	const [busyLabel, setBusyLabel] = useState("Working...");
 
 	const loadInstances = useCallback(async () => {
 		setLoading(true);
@@ -135,6 +137,7 @@ export const InstanceList = ({
 		sshKeyIds?: string[],
 	) => {
 		setBusyInstanceId(instanceId);
+		setBusyLabel("Starting...");
 		try {
 			await startInstance(
 				projectId,
@@ -156,6 +159,7 @@ export const InstanceList = ({
 
 	const handleStop = async (instanceId: string) => {
 		setBusyInstanceId(instanceId);
+		setBusyLabel("Stopping...");
 		try {
 			await stopInstance(projectId, repoId, instanceId);
 			setStopConfirmId(null);
@@ -173,6 +177,7 @@ export const InstanceList = ({
 		sshKeyIds?: string[],
 	) => {
 		setBusyInstanceId(instanceId);
+		setBusyLabel("Restarting...");
 		try {
 			await restartInstance(
 				projectId,
@@ -195,6 +200,7 @@ export const InstanceList = ({
 	const handleDelete = async (instanceId: string) => {
 		if (!confirm("Are you sure you want to delete this instance?")) return;
 		setBusyInstanceId(instanceId);
+		setBusyLabel("Deleting...");
 		try {
 			await deleteInstance(projectId, repoId, instanceId);
 			// Update state immediately instead of reloading
@@ -250,6 +256,10 @@ export const InstanceList = ({
 				<div className="instance-grid">
 					{instances.map((instance) => (
 						<div key={instance.id} className="instance-card">
+							<LoadingOverlay
+								visible={busyInstanceId === instance.id}
+								label={busyLabel}
+							/>
 							<div className="instance-info">
 								<div className="instance-name">{instance.display_name}</div>
 								<div className="instance-meta">
diff --git a/apps/web/src/components/features/tool/tool-starter.tsx b/apps/web/src/components/features/tool/tool-starter.tsx
index 5a20337..7cef793 100644
--- a/apps/web/src/components/features/tool/tool-starter.tsx
+++ b/apps/web/src/components/features/tool/tool-starter.tsx
@@ -2,6 +2,7 @@
 
 import { useState, useEffect, useCallback } from "react";
 import { Icon } from "../../icon";
+import { LoadingOverlay } from "../../loading-overlay";
 import { listToolTypes, type ToolType } from "../../../api/tool-types";
 import {
 	listConfigProfiles,
@@ -172,6 +173,7 @@ export function ToolStarter({
 
 	return (
 		<div className="tool-starter">
+			<LoadingOverlay visible={starting} label="Starting tool..." />
 			{/* Context header — read-only workspace info */}
 			<div className="tool-starter-context">
 				<div className="context-row">
diff --git a/apps/web/src/components/loading-overlay.tsx b/apps/web/src/components/loading-overlay.tsx
new file mode 100644
index 0000000..64edff3
--- /dev/null
+++ b/apps/web/src/components/loading-overlay.tsx
@@ -0,0 +1,21 @@
+import { Icon } from "./icon";
+
+interface LoadingOverlayProps {
+	visible: boolean;
+	label?: string;
+}
+
+export function LoadingOverlay({ visible, label }: LoadingOverlayProps) {
+	if (!visible) return null;
+
+	return (
+		<div className="loading-overlay" aria-live="polite">
+			<div className="loading-overlay-content">
+				<Icon name="loading" size="lg" className="icon-spin" ariaLabel={label} />
+				{label && (
+					<span className="loading-overlay-label">{label}</span>
+				)}
+			</div>
+		</div>
+	);
+}
diff --git a/apps/web/src/styles/utilities.css b/apps/web/src/styles/utilities.css
index a6a6922..18ed2e0 100644
--- a/apps/web/src/styles/utilities.css
+++ b/apps/web/src/styles/utilities.css
@@ -383,6 +383,51 @@ a.nav-item,
 	align-items: center;
 }
 
+/* ============================================
+   Loading Overlay
+   ============================================ */
+
+.loading-overlay {
+	position: absolute;
+	inset: 0;
+	background: rgba(0, 0, 0, 0.12);
+	backdrop-filter: blur(1px);
+	border-radius: inherit;
+	display: flex;
+	align-items: center;
+	justify-content: center;
+	z-index: 10;
+}
+
+.loading-overlay-content {
+	display: flex;
+	flex-direction: column;
+	align-items: center;
+	gap: var(--space-2);
+	color: var(--text, currentColor);
+}
+
+.loading-overlay-label {
+	font-size: var(--text-sm);
+	font-weight: 500;
+}
+
+.icon-spin {
+	animation: icon-spin 1s linear infinite;
+}
+
+@keyframes icon-spin {
+	to {
+		transform: rotate(360deg);
+	}
+}
+
+.session-card,
+.tool-starter,
+.create-session-form-wrapper {
+	position: relative;
+}
+
 /* ============================================
    Terminal Styles
    ============================================ */