diff --git a/docs/resources/kubernetes_project.md b/docs/resources/kubernetes_project.md
index 13273f11..57c22c14 100644
--- a/docs/resources/kubernetes_project.md
+++ b/docs/resources/kubernetes_project.md
@@ -39,7 +39,7 @@ resource "stackit_kubernetes_project" "example" {
 
 ### Required
 
-- `project_id` (String) the project ID that SKE will be enabled in
+- `project_id` (String) the project UUID that SKE will be enabled in
 
 ### Optional
 
diff --git a/stackit/internal/resources/kubernetes/project/schema.go b/stackit/internal/resources/kubernetes/project/schema.go
index b3534fc3..e224680e 100644
--- a/stackit/internal/resources/kubernetes/project/schema.go
+++ b/stackit/internal/resources/kubernetes/project/schema.go
@@ -5,11 +5,13 @@ import (
 	"fmt"
 
 	"github.com/SchwarzIT/terraform-provider-stackit/stackit/internal/common"
+	"github.com/SchwarzIT/terraform-provider-stackit/stackit/pkg/validate"
 	"github.com/hashicorp/terraform-plugin-framework-timeouts/resource/timeouts"
 	"github.com/hashicorp/terraform-plugin-framework/resource"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/planmodifier"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/stringplanmodifier"
+	"github.com/hashicorp/terraform-plugin-framework/schema/validator"
 	"github.com/hashicorp/terraform-plugin-framework/types"
 )
 
@@ -38,8 +40,11 @@ func (r *Resource) Schema(ctx context.Context, req resource.SchemaRequest, resp
 			},
 
 			"project_id": schema.StringAttribute{
-				Description: "the project ID that SKE will be enabled in",
+				Description: "the project UUID that SKE will be enabled in",
 				Required:    true,
+				Validators: []validator.String{
+					validate.ProjectID(),
+				},
 			},
 
 			"timeouts": common.Timeouts(ctx, timeouts.Opts{