diff --git a/auth/oauth2adapt/go.mod b/auth/oauth2adapt/go.mod
index 504228c..f30b79f 100644
--- a/auth/oauth2adapt/go.mod
+++ b/auth/oauth2adapt/go.mod
@@ -3,15 +3,9 @@
 go 1.19
 
 require (
-	cloud.google.com/go/auth v0.1.1
+	cloud.google.com/go/auth v0.2.0
 	github.com/google/go-cmp v0.6.0
-	golang.org/x/oauth2 v0.18.0
+	golang.org/x/oauth2 v0.19.0
 )
 
-require (
-	github.com/golang/protobuf v1.5.3 // indirect
-	golang.org/x/crypto v0.21.0 // indirect
-	golang.org/x/sys v0.18.0 // indirect
-	google.golang.org/appengine v1.6.8 // indirect
-	google.golang.org/protobuf v1.33.0 // indirect
-)
+require cloud.google.com/go/compute/metadata v0.3.0 // indirect
diff --git a/auth/oauth2adapt/go.sum b/auth/oauth2adapt/go.sum
index e86c4c0..8b29eb2 100644
--- a/auth/oauth2adapt/go.sum
+++ b/auth/oauth2adapt/go.sum
@@ -1,56 +1,20 @@
-cloud.google.com/go/auth v0.1.1 h1:8Wr6IGukdRVnnjA4ZpmHmSEW+9GHGR/Qd7+/Xx1WJIw=
-cloud.google.com/go/auth v0.1.1/go.mod h1:v711jlP5djxKNHuG7AizNCHLRNhzsOljrMQkzu4eZT4=
-cloud.google.com/go/compute v1.23.3 h1:6sVlXXBmbd7jNX0Ipq0trII3e4n1/MsADLK6a+aiVlk=
-cloud.google.com/go/compute/metadata v0.2.3 h1:mg4jlk7mCAj6xXp9UJ4fjI9VUI5rubuGBW5aJ7UnBMY=
+cloud.google.com/go/auth v0.2.0 h1:y6oTcpMSbOcXbwYgUUrvI+mrQ2xbrcdpPgtVbCGTLTk=
+cloud.google.com/go/auth v0.2.0/go.mod h1:+yb+oy3/P0geX6DLKlqiGHARGR6EX2GRtYCzWOCQSbU=
+cloud.google.com/go/compute/metadata v0.3.0 h1:Tz+eQXMEqDIKRsmY3cHTL6FVaynIjX2QxYC4trgAKZc=
+cloud.google.com/go/compute/metadata v0.3.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1hT1fIilQDwofLpJ20k=
 github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da h1:oI5xCqsCo564l8iNU+DwB5epxmsaqB+rhGL0m5jtYqE=
-github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
-github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
-github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
-github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
-github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/s2a-go v0.1.7 h1:60BLSyTrOV4/haCDW4zb1guZItoSq8foHCXrAnjBo/o=
 github.com/googleapis/enterprise-certificate-proxy v0.3.2 h1:Vie5ybvEvT75RniqhfFxPRy3Bf7vr3h0cechB90XaQs=
-github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 go.opencensus.io v0.24.0 h1:y73uSU6J157QMP2kn2r30vwW1A2W2WFwSCGnAVxeaD0=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.21.0 h1:X31++rzVUdKhX5sWmSOFZxx8UW/ldWx55cbf08iNAMA=
-golang.org/x/crypto v0.21.0/go.mod h1:0BP7YvVV9gBbVKyeTG0Gyn+gZm94bibOW5BjDEYAOMs=
-golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
-golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.22.0 h1:9sGLhx7iRIHEiX0oAJ3MRZMUCElJgy7Br1nO+AMN3Tc=
-golang.org/x/oauth2 v0.18.0 h1:09qnuIAgzdx1XplqJvW6CQqMCtGZykZWcXzPMPUusvI=
-golang.org/x/oauth2 v0.18.0/go.mod h1:Wf7knwG0MPoWIMMBgFlEaSUDaKskp0dCfrlJRJXbBi8=
-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/oauth2 v0.19.0 h1:9+E/EZBCbTLNrbN35fHv/a/d/mOBatymz1zbtQrXpIg=
+golang.org/x/oauth2 v0.19.0/go.mod h1:vYi7skDa1x015PmRRYZ7+s1cWyPgrPiSYRe4rnsexc8=
 golang.org/x/sys v0.18.0 h1:DBdB3niSjOA/O0blCZBqDefyWNYveAYMNF1Wum0DYQ4=
-golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
-golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
-golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-google.golang.org/appengine v1.6.8 h1:IhEN5q69dyKagZPYMSdIjS2HqprW324FRQZJcGqPAsM=
-google.golang.org/appengine v1.6.8/go.mod h1:1jJ3jBArFh5pcgW8gCtRJnepW8FzD1V44FJffLiz/Ds=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80 h1:AjyfHzEPEFp/NpvfN5g+KDla3EMojjhRVZc1i7cj+oM=
-google.golang.org/grpc v1.62.0 h1:HQKZ/fa1bXkX1oFOvSjmZEUL8wLSaZTjCcLAlmZRtdk=
-google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
-google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240415180920-8c6c420018be h1:LG9vZxsWGOmUKieR8wPAUR3u3MpnYFQZROPIMaXh7/A=
+google.golang.org/grpc v1.63.0 h1:WjKe+dnvABXyPJMD7KDNLxtoGk5tgk+YFWN6cBWjZE8=
 google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
-google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
diff --git a/auth/oauth2adapt/oauth2adapt.go b/auth/oauth2adapt/oauth2adapt.go
index c6add6e..897b59f 100644
--- a/auth/oauth2adapt/oauth2adapt.go
+++ b/auth/oauth2adapt/oauth2adapt.go
@@ -23,6 +23,7 @@
 
 	"cloud.google.com/go/auth"
 	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
 )
 
 // TokenProviderFromTokenSource converts any [golang.org/x/oauth2.TokenSource]
@@ -80,6 +81,44 @@
 	}, nil
 }
 
+// AuthCredentialsFromOauth2Credentials converts a [golang.org/x/oauth2/google.Credentials]
+// to a [cloud.google.com/go/auth.Credentials].
+func AuthCredentialsFromOauth2Credentials(creds *google.Credentials) *auth.Credentials {
+	if creds == nil {
+		return nil
+	}
+	return auth.NewCredentials(&auth.CredentialsOptions{
+		TokenProvider: TokenProviderFromTokenSource(creds.TokenSource),
+		JSON:          creds.JSON,
+		ProjectIDProvider: auth.CredentialsPropertyFunc(func(ctx context.Context) (string, error) {
+			return creds.ProjectID, nil
+		}),
+		UniverseDomainProvider: auth.CredentialsPropertyFunc(func(ctx context.Context) (string, error) {
+			return creds.GetUniverseDomain()
+		}),
+	})
+}
+
+// Oauth2CredentialsFromAuthCredentials converts a [cloud.google.com/go/auth.Credentials]
+// to a [golang.org/x/oauth2/google.Credentials].
+func Oauth2CredentialsFromAuthCredentials(creds *auth.Credentials) *google.Credentials {
+	if creds == nil {
+		return nil
+	}
+	// Throw away errors as old credentials are not request aware. Also, no
+	// network requests are currently happening for this use case.
+	projectID, _ := creds.ProjectID(context.Background())
+
+	return &google.Credentials{
+		TokenSource: TokenSourceFromTokenProvider(creds.TokenProvider),
+		ProjectID:   projectID,
+		JSON:        creds.JSON(),
+		UniverseDomainProvider: func() (string, error) {
+			return creds.UniverseDomain(context.Background())
+		},
+	}
+}
+
 type oauth2Error struct {
 	ErrorCode        string `json:"error"`
 	ErrorDescription string `json:"error_description"`
diff --git a/auth/oauth2adapt/oauth2adapt_test.go b/auth/oauth2adapt/oauth2adapt_test.go
index 388c0ac..5ea923b 100644
--- a/auth/oauth2adapt/oauth2adapt_test.go
+++ b/auth/oauth2adapt/oauth2adapt_test.go
@@ -23,6 +23,7 @@
 	"cloud.google.com/go/auth"
 	"github.com/google/go-cmp/cmp"
 	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
 )
 
 func TestTokenProviderFromTokenSource(t *testing.T) {
@@ -140,6 +141,108 @@
 	}
 }
 
+func TestAuthCredentialsFromOauth2Credentials(t *testing.T) {
+	ctx := context.Background()
+	inputCreds := &google.Credentials{
+		ProjectID:   "test_project",
+		TokenSource: tokenSource{token: "token"},
+		JSON:        []byte("json"),
+		UniverseDomainProvider: func() (string, error) {
+			return "domain", nil
+		},
+	}
+	outCreds := AuthCredentialsFromOauth2Credentials(inputCreds)
+
+	gotProject, err := outCreds.ProjectID(ctx)
+	if err != nil {
+		t.Fatalf("outCreds.ProjectID() = %v", err)
+	}
+	if want := inputCreds.ProjectID; gotProject != want {
+		t.Fatalf("got %q, want %q", gotProject, want)
+	}
+
+	gotToken, err := outCreds.Token(ctx)
+	if err != nil {
+		t.Fatalf("outCreds.Token() = %v", err)
+	}
+	wantTok, err := inputCreds.TokenSource.Token()
+	if err != nil {
+		t.Fatalf("inputCreds.TokenSource.Token() = %v", err)
+	}
+	if gotToken.Value != wantTok.AccessToken {
+		t.Fatalf("got %q, want %q", gotToken.Value, wantTok.AccessToken)
+	}
+
+	gotJSON := outCreds.JSON()
+	if want := inputCreds.JSON; !cmp.Equal(gotJSON, want) {
+		t.Fatalf("got %s, want %s", gotJSON, want)
+	}
+
+	gotUD, err := outCreds.UniverseDomain(ctx)
+	if err != nil {
+		t.Fatalf("outCreds.UniverseDomain() = %v", err)
+	}
+	wantUD, err := inputCreds.GetUniverseDomain()
+	if err != nil {
+		t.Fatalf("inputCreds.GetUniverseDomain() = %v", err)
+	}
+	if gotUD != wantUD {
+		t.Fatalf("got %q, want %q", wantUD, wantUD)
+	}
+}
+
+func TestOauth2CredentialsFromAuthCredentials(t *testing.T) {
+	ctx := context.Background()
+	inputCreds := auth.NewCredentials(&auth.CredentialsOptions{
+		ProjectIDProvider: auth.CredentialsPropertyFunc(func(ctx context.Context) (string, error) {
+			return "project", nil
+		}),
+		TokenProvider: tokenProvider{token: "token"},
+		JSON:          []byte("json"),
+		UniverseDomainProvider: auth.CredentialsPropertyFunc(func(ctx context.Context) (string, error) {
+			return "domain", nil
+		}),
+	})
+	outCreds := Oauth2CredentialsFromAuthCredentials(inputCreds)
+
+	wantProject, err := inputCreds.ProjectID(ctx)
+	if err != nil {
+		t.Fatalf("inputCreds.ProjectID() = %v", err)
+	}
+	if outCreds.ProjectID != wantProject {
+		t.Fatalf("got %q, want %q", outCreds.ProjectID, wantProject)
+	}
+
+	gotToken, err := inputCreds.Token(ctx)
+	if err != nil {
+		t.Fatalf("inputCreds.Token() = %v", err)
+	}
+	wantTok, err := outCreds.TokenSource.Token()
+	if err != nil {
+		t.Fatalf("outCreds.TokenSource.Token() = %v", err)
+	}
+	if gotToken.Value != wantTok.AccessToken {
+		t.Fatalf("got %q, want %q", gotToken.Value, wantTok.AccessToken)
+	}
+
+	wantJSON := inputCreds.JSON()
+	if !cmp.Equal(outCreds.JSON, wantJSON) {
+		t.Fatalf("got %s, want %s", outCreds.JSON, wantJSON)
+	}
+
+	wantUD, err := inputCreds.UniverseDomain(ctx)
+	if err != nil {
+		t.Fatalf("outCreds.UniverseDomain() = %v", err)
+	}
+	gotUD, err := outCreds.GetUniverseDomain()
+	if err != nil {
+		t.Fatalf("inputCreds.GetUniverseDomain() = %v", err)
+	}
+	if gotUD != wantUD {
+		t.Fatalf("got %q, want %q", wantUD, wantUD)
+	}
+}
+
 type tokenSource struct {
 	token string
 	err   error