diff --git a/src/ZB.MOM.WW.ScadaBridge.DeploymentManager/DeploymentService.cs b/src/ZB.MOM.WW.ScadaBridge.DeploymentManager/DeploymentService.cs
index 3e405507..321d6fe6 100644
--- a/src/ZB.MOM.WW.ScadaBridge.DeploymentManager/DeploymentService.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.DeploymentManager/DeploymentService.cs
@@ -563,6 +563,37 @@ public class DeploymentService
             instance.UniqueName, _options.OperationLockTimeout, cancellationToken);
 
         var commandId = Guid.NewGuid().ToString("N");
+
+        // A NotDeployed instance has no live Instance Actor at any site, so Delete is
+        // a pure central-side record cleanup -- there is nothing to tear down at the
+        // site and no reason to require the site be reachable. Transport-imported
+        // instances always land NotDeployed (often against an uncommissioned or
+        // unreachable site), so a site round-trip here would make them undeletable
+        // until their site comes online. Skip the site entirely and remove the record.
+        if (instance.State == InstanceState.NotDeployed)
+        {
+            try
+            {
+                await _repository.DeleteInstanceAsync(instanceId, cancellationToken);
+                await _repository.SaveChangesAsync(cancellationToken);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex,
+                    "Failed to delete NotDeployed instance {Instance} centrally", instance.UniqueName);
+                return Result<InstanceLifecycleResponse>.Failure(
+                    $"Delete failed: the central record for '{instance.UniqueName}' could not be removed: {ex.Message}.");
+            }
+
+            await TryLogAuditAsync(user, "Delete", "Instance", instanceId.ToString(),
+                instance.UniqueName,
+                new { CommandId = commandId, Success = true, SiteRoundTripSkipped = true },
+                cancellationToken);
+
+            return Result<InstanceLifecycleResponse>.Success(new InstanceLifecycleResponse(
+                commandId, instance.UniqueName, Success: true, ErrorMessage: null, DateTimeOffset.UtcNow));
+        }
+
         var siteId = await ResolveSiteIdentifierAsync(instance.SiteId, cancellationToken);
         var command = new DeleteInstanceCommand(commandId, instance.UniqueName, DateTimeOffset.UtcNow);
 
diff --git a/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/DeploymentServiceTests.cs b/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/DeploymentServiceTests.cs
index ddcb4801..7cc6467f 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/DeploymentServiceTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/DeploymentServiceTests.cs
@@ -454,6 +454,25 @@ public class DeploymentServiceTests : TestKit
         Assert.Contains("not found", result.Error);
     }
 
+    [Fact]
+    public async Task DeleteInstanceAsync_NotDeployed_RemovesRecordWithoutSiteRoundTrip()
+    {
+        // #05-T18: a NotDeployed instance has no live actor at any site (Transport-
+        // imported instances always land NotDeployed, often against an uncommissioned
+        // or unreachable site). Delete must succeed as a central-side record cleanup
+        // WITHOUT contacting the site. The default _service's CommunicationService has
+        // no actor wired, so any attempted site round-trip throws uncaught -- a Success
+        // result therefore proves the site was never contacted (Times.Never, enforced
+        // structurally).
+        var instance = new Instance("ImportedInst") { Id = 70, SiteId = 1, State = InstanceState.NotDeployed };
+        _repo.GetInstanceByIdAsync(70, Arg.Any<CancellationToken>()).Returns(instance);
+
+        var result = await _service.DeleteInstanceAsync(70, "admin");
+
+        Assert.True(result.IsSuccess);
+        await _repo.Received(1).DeleteInstanceAsync(70, Arg.Any<CancellationToken>());
+    }
+
     // ── DeploymentManager-004: site-success but central-delete-failure must not escape uncaught ──
 
     [Fact]