diff --git a/docs/release-notes/26_3_0.adoc b/docs/release-notes/26_3_0.adoc
index 5696378..9ab72fc 100644
--- a/docs/release-notes/26_3_0.adoc
+++ b/docs/release-notes/26_3_0.adoc
@@ -1,4 +1,4 @@
-This release of Keycloak JS deprecates the built-in Cordova adapters ahead of their removal in the next major version.
+This release of Keycloak JS deprecates the built-in Cordova adapters and the use of unbound methods ahead of their removal in the next major version.
 
 == Deprecations
 
@@ -19,3 +19,19 @@ This decision was made after extensive discussion with the community (https://gi
 ==== Migration
 
 If you are using Cordova or a similar hybrid app framework, use a <<custom-adapters,custom adapter>> to provide your own implementation. For users migrating to Capacitor, see https://github.com/keycloak/keycloak-js/issues/27[keycloak/keycloak-js#27] for an ongoing discussion on improving the custom adapter interface to better support this use case.
+
+=== Calling methods without a bound `this` is deprecated
+
+Destructuring methods from a `Keycloak` instance (e.g. `const { login } = keycloak`) and calling them without their original `this` context is now deprecated. A deprecation warning will be emitted in the browser console the first time an unbound method is called. In the next major version, this pattern will stop working entirely.
+
+Instead, always call methods directly on the instance:
+
+[source,javascript]
+----
+// Deprecated:
+const { login, logout } = keycloak;
+login();
+
+// Recommended:
+keycloak.login();
+----
diff --git a/lib/deprecations.js b/lib/deprecations.js
index 1892f2e..6f69d39 100644
--- a/lib/deprecations.js
+++ b/lib/deprecations.js
@@ -14,3 +14,25 @@ export function logDeprecation (code, message) {
   emitted.add(code)
   console.warn(`[KEYCLOAK] ${code}: ${message}`)
 }
+
+/**
+ * Replaces each listed method on the instance with a bound wrapper that
+ * emits a deprecation warning when called with an unbound `this`.
+ * @param {object} instance
+ * @param {string} code
+ * @param {string[]} methods
+ */
+export function deprecatedBoundMethods (instance, code, methods) {
+  for (const name of methods) {
+    const original = instance[name]
+    instance[name] = function (...args) {
+      if (this !== instance) {
+        logDeprecation(
+          `${code}:${name}`,
+          `Calling '${name}()' without a bound 'this' is deprecated and will stop working in a future major version.`
+        )
+      }
+      return original.apply(instance, args)
+    }
+  }
+}
diff --git a/lib/keycloak.js b/lib/keycloak.js
index 7afa0be..c290b20 100755
--- a/lib/keycloak.js
+++ b/lib/keycloak.js
@@ -19,7 +19,7 @@
  * limitations under the License.
  */
 
-import { logDeprecation } from './deprecations.js'
+import { deprecatedBoundMethods, logDeprecation } from './deprecations.js'
 
 const CONTENT_TYPE_JSON = 'application/json'
 
@@ -168,13 +168,20 @@ export default class Keycloak {
     }
 
     this.#config = config
+
+    deprecatedBoundMethods(this, 'KC-DEP-003', [
+      'init', 'login', 'createLoginUrl', 'logout', 'createLogoutUrl', 'register',
+      'createRegisterUrl', 'createAccountUrl', 'accountManagement', 'hasRealmRole',
+      'hasResourceRole', 'loadUserProfile', 'loadUserInfo', 'isTokenExpired',
+      'updateToken', 'clearToken'
+    ])
   }
 
   /**
    * @param {KeycloakInitOptions} initOptions
    * @returns {Promise<boolean>}
    */
-  init = async (initOptions = {}) => {
+  async init (initOptions = {}) {
     if (this.didInitialize) {
       throw new Error("A 'Keycloak' instance can only be initialized once.")
     }
@@ -1196,7 +1203,7 @@ export default class Keycloak {
    * @param {KeycloakLoginOptions} [options]
    * @returns {Promise<void>}
    */
-  login = (options) => {
+  login (options) {
     return this.#adapter.login(options)
   }
 
@@ -1204,7 +1211,7 @@ export default class Keycloak {
    * @param {KeycloakLoginOptions} [options]
    * @returns {Promise<string>}
    */
-  createLoginUrl = async (options) => {
+  async createLoginUrl (options) {
     const state = createUUID()
     const nonce = createUUID()
     const redirectUri = this.#adapter.redirectUri(options)
@@ -1302,7 +1309,7 @@ export default class Keycloak {
    * @param {KeycloakLogoutOptions} [options]
    * @returns {Promise<void>}
    */
-  logout = (options) => {
+  logout (options) {
     return this.#adapter.logout(options)
   }
 
@@ -1310,7 +1317,7 @@ export default class Keycloak {
    * @param {KeycloakLogoutOptions} [options]
    * @returns {string}
    */
-  createLogoutUrl = (options) => {
+  createLogoutUrl (options) {
     const logoutMethod = options?.logoutMethod ?? this.logoutMethod
     const url = this.endpoints.logout()
 
@@ -1334,7 +1341,7 @@ export default class Keycloak {
    * @param {KeycloakRegisterOptions} [options]
    * @returns {Promise<void>}
    */
-  register = (options) => {
+  register (options) {
     return this.#adapter.register(options)
   }
 
@@ -1342,7 +1349,7 @@ export default class Keycloak {
    * @param {KeycloakRegisterOptions} [options]
    * @returns {Promise<string>}
    */
-  createRegisterUrl = (options) => {
+  createRegisterUrl (options) {
     return this.createLoginUrl({ ...options, action: 'register' })
   }
 
@@ -1350,7 +1357,7 @@ export default class Keycloak {
    * @param {KeycloakAccountOptions} [options]
    * @returns {string}
    */
-  createAccountUrl = (options) => {
+  createAccountUrl (options) {
     const url = this.#getRealmUrl()
 
     if (!url) {
@@ -1368,7 +1375,7 @@ export default class Keycloak {
   /**
    * @returns {Promise<void>}
    */
-  accountManagement = () => {
+  accountManagement () {
     return this.#adapter.accountManagement()
   }
 
@@ -1376,7 +1383,7 @@ export default class Keycloak {
    * @param {string} role
    * @returns {boolean}
    */
-  hasRealmRole = (role) => {
+  hasRealmRole (role) {
     const access = this.realmAccess
     return !!access && access.roles.indexOf(role) >= 0
   }
@@ -1386,7 +1393,7 @@ export default class Keycloak {
    * @param {string} [resource]
    * @returns {boolean}
    */
-  hasResourceRole = (role, resource) => {
+  hasResourceRole (role, resource) {
     if (!this.resourceAccess) {
       return false
     }
@@ -1398,7 +1405,7 @@ export default class Keycloak {
   /**
    * @returns {Promise<KeycloakProfile>}
    */
-  loadUserProfile = async () => {
+  async loadUserProfile () {
     const realmUrl = this.#getRealmUrl()
 
     if (!realmUrl) {
@@ -1417,7 +1424,7 @@ export default class Keycloak {
   /**
    * @returns {Promise<{}>}
    */
-  loadUserInfo = async () => {
+  async loadUserInfo () {
     const url = this.endpoints.userinfo()
     /** @type {{}} */
     const userInfo = await fetchJSON(url, {
@@ -1431,7 +1438,7 @@ export default class Keycloak {
    * @param {number} [minValidity]
    * @returns {boolean}
    */
-  isTokenExpired = (minValidity) => {
+  isTokenExpired (minValidity) {
     if (!this.tokenParsed || (!this.refreshToken && this.flow !== 'implicit')) {
       throw new Error('Not authenticated')
     }
@@ -1459,7 +1466,7 @@ export default class Keycloak {
    * @param {number} minValidity
    * @returns {Promise<boolean>}
    */
-  updateToken = async (minValidity) => {
+  async updateToken (minValidity) {
     if (!this.refreshToken) {
       throw new Error('Unable to update token, no refresh token available.')
     }
@@ -1522,7 +1529,7 @@ export default class Keycloak {
     return await promise
   }
 
-  clearToken = () => {
+  clearToken () {
     if (this.token) {
       this.#setToken()
       this.onAuthLogout?.()