diff --git a/FirebaseAuth/Sources/Swift/AuthProvider/AuthCredential.swift b/FirebaseAuth/Sources/Swift/AuthProvider/AuthCredential.swift
index 0500875b10f..2ae683ae22b 100644
--- a/FirebaseAuth/Sources/Swift/AuthProvider/AuthCredential.swift
+++ b/FirebaseAuth/Sources/Swift/AuthProvider/AuthCredential.swift
@@ -16,7 +16,7 @@ import Foundation
 
 /// Public representation of a credential.
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-@objc(FIRAuthCredential) open class AuthCredential: NSObject {
+@objc(FIRAuthCredential) open class AuthCredential: NSObject, @unchecked Sendable {
   /// The name of the identity provider for the credential.
   @objc public let provider: String
 
diff --git a/FirebaseAuth/Sources/Swift/AuthProvider/EmailAuthProvider.swift b/FirebaseAuth/Sources/Swift/AuthProvider/EmailAuthProvider.swift
index 050dce30974..e87445b84a2 100644
--- a/FirebaseAuth/Sources/Swift/AuthProvider/EmailAuthProvider.swift
+++ b/FirebaseAuth/Sources/Swift/AuthProvider/EmailAuthProvider.swift
@@ -38,7 +38,8 @@ import Foundation
 }
 
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-@objc(FIREmailPasswordAuthCredential) class EmailAuthCredential: AuthCredential, NSSecureCoding {
+@objc(FIREmailPasswordAuthCredential) class EmailAuthCredential: AuthCredential, NSSecureCoding,
+  @unchecked Sendable {
   let email: String
 
   enum EmailType {
diff --git a/FirebaseAuth/Sources/Swift/AuthProvider/FacebookAuthProvider.swift b/FirebaseAuth/Sources/Swift/AuthProvider/FacebookAuthProvider.swift
index cc89e7b3394..59cb2385425 100644
--- a/FirebaseAuth/Sources/Swift/AuthProvider/FacebookAuthProvider.swift
+++ b/FirebaseAuth/Sources/Swift/AuthProvider/FacebookAuthProvider.swift
@@ -34,7 +34,8 @@ import Foundation
 }
 
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-@objc(FIRFacebookAuthCredential) class FacebookAuthCredential: AuthCredential, NSSecureCoding {
+@objc(FIRFacebookAuthCredential) class FacebookAuthCredential: AuthCredential, NSSecureCoding,
+  @unchecked Sendable {
   let accessToken: String
 
   init(withAccessToken accessToken: String) {
diff --git a/FirebaseAuth/Sources/Swift/AuthProvider/GameCenterAuthProvider.swift b/FirebaseAuth/Sources/Swift/AuthProvider/GameCenterAuthProvider.swift
index 4560bad9aaf..82836ee81b0 100644
--- a/FirebaseAuth/Sources/Swift/AuthProvider/GameCenterAuthProvider.swift
+++ b/FirebaseAuth/Sources/Swift/AuthProvider/GameCenterAuthProvider.swift
@@ -129,7 +129,7 @@
 
   @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
   @objc(FIRGameCenterAuthCredential)
-  class GameCenterAuthCredential: AuthCredential, NSSecureCoding {
+  class GameCenterAuthCredential: AuthCredential, NSSecureCoding, @unchecked Sendable {
     let playerID: String
     let teamPlayerID: String?
     let gamePlayerID: String?
diff --git a/FirebaseAuth/Sources/Swift/AuthProvider/GitHubAuthProvider.swift b/FirebaseAuth/Sources/Swift/AuthProvider/GitHubAuthProvider.swift
index 801e63fa8ee..75b914cbb7a 100644
--- a/FirebaseAuth/Sources/Swift/AuthProvider/GitHubAuthProvider.swift
+++ b/FirebaseAuth/Sources/Swift/AuthProvider/GitHubAuthProvider.swift
@@ -34,7 +34,8 @@ import Foundation
 }
 
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-@objc(FIRGitHubAuthCredential) class GitHubAuthCredential: AuthCredential, NSSecureCoding {
+@objc(FIRGitHubAuthCredential) class GitHubAuthCredential: AuthCredential, NSSecureCoding,
+  @unchecked Sendable {
   let token: String
 
   init(withToken token: String) {
diff --git a/FirebaseAuth/Sources/Swift/AuthProvider/GoogleAuthProvider.swift b/FirebaseAuth/Sources/Swift/AuthProvider/GoogleAuthProvider.swift
index 41f223b25dc..0f41ac69ce3 100644
--- a/FirebaseAuth/Sources/Swift/AuthProvider/GoogleAuthProvider.swift
+++ b/FirebaseAuth/Sources/Swift/AuthProvider/GoogleAuthProvider.swift
@@ -36,7 +36,8 @@ import Foundation
 }
 
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-@objc(FIRGoogleAuthCredential) class GoogleAuthCredential: AuthCredential, NSSecureCoding {
+@objc(FIRGoogleAuthCredential) class GoogleAuthCredential: AuthCredential, NSSecureCoding,
+  @unchecked Sendable {
   let idToken: String
   let accessToken: String
 
diff --git a/FirebaseAuth/Sources/Swift/AuthProvider/OAuthCredential.swift b/FirebaseAuth/Sources/Swift/AuthProvider/OAuthCredential.swift
index 920fd138af4..8029fd6df51 100644
--- a/FirebaseAuth/Sources/Swift/AuthProvider/OAuthCredential.swift
+++ b/FirebaseAuth/Sources/Swift/AuthProvider/OAuthCredential.swift
@@ -16,7 +16,8 @@ import Foundation
 
 /// Internal implementation of `AuthCredential` for generic credentials.
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-@objc(FIROAuthCredential) open class OAuthCredential: AuthCredential, NSSecureCoding {
+@objc(FIROAuthCredential) open class OAuthCredential: AuthCredential, NSSecureCoding,
+  @unchecked Sendable {
   /// The ID Token associated with this credential.
   @objc(IDToken) public let idToken: String?
 
diff --git a/FirebaseAuth/Sources/Swift/AuthProvider/PhoneAuthCredential.swift b/FirebaseAuth/Sources/Swift/AuthProvider/PhoneAuthCredential.swift
index 49f643a34d1..a930fadc2eb 100644
--- a/FirebaseAuth/Sources/Swift/AuthProvider/PhoneAuthCredential.swift
+++ b/FirebaseAuth/Sources/Swift/AuthProvider/PhoneAuthCredential.swift
@@ -18,7 +18,8 @@ import Foundation
 ///
 /// This class is available on iOS only.
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-@objc(FIRPhoneAuthCredential) open class PhoneAuthCredential: AuthCredential, NSSecureCoding {
+@objc(FIRPhoneAuthCredential) open class PhoneAuthCredential: AuthCredential, NSSecureCoding,
+  @unchecked Sendable {
   enum CredentialKind {
     case phoneNumber(_ phoneNumber: String, _ temporaryProof: String)
     case verification(_ id: String, _ code: String)
diff --git a/FirebaseAuth/Sources/Swift/AuthProvider/TwitterAuthProvider.swift b/FirebaseAuth/Sources/Swift/AuthProvider/TwitterAuthProvider.swift
index 6364241188f..f9c32f9d5ad 100644
--- a/FirebaseAuth/Sources/Swift/AuthProvider/TwitterAuthProvider.swift
+++ b/FirebaseAuth/Sources/Swift/AuthProvider/TwitterAuthProvider.swift
@@ -35,7 +35,8 @@ import Foundation
 }
 
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-@objc(FIRTwitterAuthCredential) class TwitterAuthCredential: AuthCredential, NSSecureCoding {
+@objc(FIRTwitterAuthCredential) class TwitterAuthCredential: AuthCredential, NSSecureCoding,
+  @unchecked Sendable {
   let token: String
   let secret: String
 
diff --git a/FirebaseAuth/Sources/Swift/Utilities/AuthRecaptchaVerifier.swift b/FirebaseAuth/Sources/Swift/Utilities/AuthRecaptchaVerifier.swift
index 6919ac40807..b5f597f8d63 100644
--- a/FirebaseAuth/Sources/Swift/Utilities/AuthRecaptchaVerifier.swift
+++ b/FirebaseAuth/Sources/Swift/Utilities/AuthRecaptchaVerifier.swift
@@ -44,7 +44,7 @@
   }
 
   @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-  class AuthRecaptchaVerifier {
+  class AuthRecaptchaVerifier: @unchecked Sendable {
     private(set) weak var auth: Auth?
     private(set) var agentConfig: AuthRecaptchaConfig?
     private(set) var tenantConfigs: [String: AuthRecaptchaConfig] = [:]