diff --git a/backend/src/routes/projects.ts b/backend/src/routes/projects.ts
index 0465805..197829b 100644
--- a/backend/src/routes/projects.ts
+++ b/backend/src/routes/projects.ts
@@ -491,6 +491,30 @@ projects.get("/:id", async ({ params, headers }) => {
     hasSubmittedFeedback = feedbackCheck.length > 0;
   }
 
+  // Check if project can be resubmitted (first submission must be on or before March 17th, 2026)
+  let canResubmit = true;
+  if (isOwner) {
+    const firstSubmission = await db
+      .select({ createdAt: projectActivityTable.createdAt })
+      .from(projectActivityTable)
+      .where(
+        and(
+          eq(projectActivityTable.projectId, parseInt(params.id)),
+          eq(projectActivityTable.action, "project_submitted"),
+        ),
+      )
+      .orderBy(projectActivityTable.createdAt)
+      .limit(1);
+
+    if (firstSubmission.length > 0) {
+      const cutoffDate = new Date("2026-03-18T00:00:00Z");
+      canResubmit = firstSubmission[0].createdAt < cutoffDate;
+    } else {
+      // Never submitted before - cannot submit new projects
+      canResubmit = false;
+    }
+  }
+
   // Calculate effective hours (subtract overlapping shipped project hours)
   // Uses activity-derived shipped dates for ordering (consistent with Airtable sync and admin review)
   const projectHours = project[0].hoursOverride ?? project[0].hours ?? 0;
@@ -533,6 +557,7 @@ projects.get("/:id", async ({ params, headers }) => {
     owner: projectOwner[0] || null,
     isOwner,
     hasSubmittedFeedback: isOwner ? hasSubmittedFeedback : undefined,
+    canResubmit: isOwner ? canResubmit : undefined,
     activity,
   };
 });
@@ -840,6 +865,27 @@ projects.post("/:id/submit", async ({ params, headers, body }) => {
     return { error: "Project cannot be submitted in current status" };
   }
 
+  // Check if this is a resubmission - if so, verify first submission was on or before March 17th
+  const firstSubmission = await db
+    .select({ createdAt: projectActivityTable.createdAt })
+    .from(projectActivityTable)
+    .where(
+      and(
+        eq(projectActivityTable.projectId, parseInt(params.id)),
+        eq(projectActivityTable.action, "project_submitted"),
+      ),
+    )
+    .orderBy(projectActivityTable.createdAt)
+    .limit(1);
+
+  if (firstSubmission.length > 0) {
+    // This is a resubmission - check if first submission was on or before March 17th, 2026
+    const cutoffDate = new Date("2026-03-18T00:00:00Z"); // Midnight March 18th = end of March 17th
+    if (firstSubmission[0].createdAt >= cutoffDate) {
+      return { error: "Resubmissions are only allowed for projects first submitted on or before March 17th" };
+    }
+  }
+
   // Sync hours from Hackatime before submitting
   if (project[0].hackatimeProject) {
     await syncSingleProject(parseInt(params.id));
diff --git a/frontend/src/routes/projects/[id]/+page.svelte b/frontend/src/routes/projects/[id]/+page.svelte
index 62374e5..4ae0374 100644
--- a/frontend/src/routes/projects/[id]/+page.svelte
+++ b/frontend/src/routes/projects/[id]/+page.svelte
@@ -74,6 +74,7 @@
 	let owner = $state<Owner | null>(null);
 	let isOwner = $state(false);
 	let isAdmin = $state(false);
+	let canResubmit = $state(true);
 	let activity = $state<ActivityEntry[]>([]);
 	let loading = $state(true);
 	let error = $state<string | null>(null);
@@ -104,6 +105,7 @@
 			project = result.project;
 			owner = result.owner;
 			isOwner = result.isOwner;
+			canResubmit = result.canResubmit ?? true;
 			activity = result.activity || [];
 		} catch (e) {
 			error = e instanceof Error ? e.message : 'Failed to load project';
@@ -454,7 +456,7 @@
 							<Send size={18} />
 							{$t.project.awaitingReview}
 						</span>
-					{:else if project.status === 'shipped'}
+					{:else if project.status === 'shipped' && canResubmit}
 						<a
 							href="/projects/{project.id}/submit"
 							class="flex flex-1 cursor-pointer items-center justify-center gap-2 rounded-full border-4 border-black bg-black px-4 py-3 text-sm font-bold text-white transition-all duration-200 hover:bg-gray-800 sm:px-6 sm:text-base"
@@ -462,6 +464,13 @@
 							<RefreshCw size={18} />
 							ship update
 						</a>
+					{:else if project.status === 'shipped' && !canResubmit}
+						<span
+							class="flex flex-1 cursor-not-allowed items-center justify-center gap-2 rounded-full border-4 border-black bg-gray-200 px-4 py-3 text-center text-sm font-bold text-gray-600 sm:px-6 sm:text-base"
+						>
+							<CheckCircle size={18} />
+							shipped
+						</span>
 					{:else if project.status === 'permanently_rejected'}
 						<span
 							class="flex flex-1 cursor-not-allowed items-center justify-center gap-2 rounded-full border-4 border-black bg-red-100 px-4 py-3 text-center text-sm font-bold text-red-600 sm:px-6 sm:text-base"
@@ -469,6 +478,13 @@
 							<XCircle size={18} />
 							{$t.project.permanentlyRejected}
 						</span>
+					{:else if !canResubmit}
+						<span
+							class="flex flex-1 cursor-not-allowed items-center justify-center gap-2 rounded-full border-4 border-black bg-gray-200 px-4 py-3 text-center text-sm font-bold text-gray-600 sm:px-6 sm:text-base"
+						>
+							<XCircle size={18} />
+							submissions closed
+						</span>
 					{:else if $tutorialActiveStore}
 						<span
 							data-tutorial="submit-button"
diff --git a/frontend/src/routes/projects/[id]/submit/+page.svelte b/frontend/src/routes/projects/[id]/submit/+page.svelte
index 1a4e1eb..a5079ca 100644
--- a/frontend/src/routes/projects/[id]/submit/+page.svelte
+++ b/frontend/src/routes/projects/[id]/submit/+page.svelte
@@ -128,6 +128,10 @@
 			if (!responseData.isOwner) {
 				throw new Error('You can only submit your own projects');
 			}
+			// Check if resubmission is allowed
+			if (responseData.canResubmit === false) {
+				throw new Error('Resubmissions are only allowed for projects first submitted on or before March 17th');
+			}
 			project = responseData.project;
 			imagePreview = project?.image || null;
 			hasSubmittedFeedbackBefore = responseData.hasSubmittedFeedback ?? false;