diff --git a/clientapi/routing/register.go b/clientapi/routing/register.go
index 2a0db6aed..1172b9d74 100644
--- a/clientapi/routing/register.go
+++ b/clientapi/routing/register.go
@@ -332,8 +332,8 @@ func validateRecaptcha(
 	return nil
 }
 
-// validateToken returns an error response if the token is invalid
-func validateToken(
+// authenticateToken returns an error response if the token is invalid
+func authenticateToken(
 	req *http.Request,
 	userAPI userapi.ClientUserAPI,
 	cfg *config.ClientAPI,
@@ -347,16 +347,25 @@ func validateToken(
 		return ErrMissingToken
 	}
 
-	exists, err := userAPI.ValidateRegistrationToken(req.Context(), token)
+	registrationToken, err := userAPI.ValidateRegistrationToken(req.Context(), token)
 
 	if err != nil {
 		return err
 	}
 
-	if !exists {
+	if registrationToken == nil {
 		return ErrInvalidToken
 	}
 
+	// Decrease available uses
+	newAttributes := make(map[string]interface{})
+	newAttributes["usesAllowed"] = *registrationToken.UsesAllowed - 1
+	_, updateErr := userAPI.PerformAdminUpdateRegistrationToken(req.Context(), token, newAttributes)
+
+	if updateErr != nil {
+		return updateErr
+	}
+
 	return nil
 }
 
@@ -769,7 +778,7 @@ func handleRegistrationFlow(
 
 	case authtypes.LoginTypeRegistrationToken:
 		// Check given token response
-		err := validateToken(req, userAPI, cfg, r.Auth.Token)
+		err := authenticateToken(req, userAPI, cfg, r.Auth.Token)
 		switch err {
 		case ErrRegistrationTokenDisabled:
 			return util.JSONResponse{Code: http.StatusForbidden, JSON: spec.Unknown(err.Error())}
diff --git a/userapi/api/api.go b/userapi/api/api.go
index 02e4f0d22..d8227ddfd 100644
--- a/userapi/api/api.go
+++ b/userapi/api/api.go
@@ -117,7 +117,7 @@ type ClientUserAPI interface {
 	QueryLocalpartForThreePID(ctx context.Context, req *QueryLocalpartForThreePIDRequest, res *QueryLocalpartForThreePIDResponse) error
 	PerformForgetThreePID(ctx context.Context, req *PerformForgetThreePIDRequest, res *struct{}) error
 	PerformSaveThreePIDAssociation(ctx context.Context, req *PerformSaveThreePIDAssociationRequest, res *struct{}) error
-	ValidateRegistrationToken(ctx context.Context, registrationToken string) (bool, error)
+	ValidateRegistrationToken(ctx context.Context, registrationToken string) (*clientapi.RegistrationToken, error)
 }
 
 type KeyBackupAPI interface {
diff --git a/userapi/internal/user_api.go b/userapi/internal/user_api.go
index f8556c109..7c4604386 100644
--- a/userapi/internal/user_api.go
+++ b/userapi/internal/user_api.go
@@ -979,10 +979,15 @@ func (a *UserInternalAPI) PerformSaveThreePIDAssociation(ctx context.Context, re
 
 const pushRulesAccountDataType = "m.push_rules"
 
-func (a *UserInternalAPI) ValidateRegistrationToken(ctx context.Context, registrationToken string) (bool, error) {
-	exists, err := a.DB.RegistrationTokenExists(ctx, registrationToken)
+func (a *UserInternalAPI) ValidateRegistrationToken(ctx context.Context, token string) (*clientapi.RegistrationToken, error) {
+	registrationToken, err := a.DB.GetRegistrationToken(ctx, token)
+
 	if err != nil {
-		return false, err
+		return nil, err
 	}
-	return exists, nil
+	if registrationToken == nil || *registrationToken.UsesAllowed == 0 || *registrationToken.ExpiryTime > int64(spec.AsTimestamp(time.Now())) {
+		return nil, nil
+	}
+
+	return registrationToken, nil
 }