diff --git a/src/app/(protected)/vendors/_components/use-vendor-deactivation.ts b/src/app/(protected)/vendors/_components/use-vendor-deactivation.ts
index b63291be..5870f7db 100644
--- a/src/app/(protected)/vendors/_components/use-vendor-deactivation.ts
+++ b/src/app/(protected)/vendors/_components/use-vendor-deactivation.ts
@@ -38,13 +38,18 @@ export function useVendorDeactivation(onSuccess?: () => void): VendorDeactivatio
   const confirm = () => {
     if (!target || target.id == null) return;
     setError(null);
-    deleteVendor.mutate(target.id, {
-      onSuccess: () => {
-        setTarget(null);
-        onSuccess?.();
+    // The dialog has shown whatever open work orders exist, so confirming here is
+    // the explicit confirmation the API requires to deactivate past them (SH-254).
+    deleteVendor.mutate(
+      { id: target.id, confirmOpenWorkOrders: (impact?.openWorkOrders.length ?? 0) > 0 },
+      {
+        onSuccess: () => {
+          setTarget(null);
+          onSuccess?.();
+        },
+        onError: (err: Error) => setError(err.message || "Failed to deactivate vendor"),
       },
-      onError: (err: Error) => setError(err.message || "Failed to deactivate vendor"),
-    });
+    );
   };
 
   return {
diff --git a/src/app/(protected)/vendors/_components/vendor-deactivation-dialog.tsx b/src/app/(protected)/vendors/_components/vendor-deactivation-dialog.tsx
index cf673b6c..a56ca3b5 100644
--- a/src/app/(protected)/vendors/_components/vendor-deactivation-dialog.tsx
+++ b/src/app/(protected)/vendors/_components/vendor-deactivation-dialog.tsx
@@ -8,11 +8,13 @@ import {
   DialogContent,
   DialogContentText,
   DialogTitle,
+  Link,
   List,
   ListItem,
   Stack,
   Typography,
 } from "@mui/material";
+import { Link as RouterLink } from "react-router";
 import type { VendorDeactivationImpact, VendorListItem } from "@/domain/vendors/types/vendor";
 
 interface VendorDeactivationDialogProps {
@@ -26,6 +28,15 @@ interface VendorDeactivationDialogProps {
   onConfirm: () => void;
 }
 
+function deactivationMessage(companyName: string | undefined, openCount: number): string {
+  const name = companyName ? `"${companyName}"` : "This vendor";
+  if (openCount === 0) {
+    return `${name} will no longer be selectable for new work orders.`;
+  }
+  const plural = openCount === 1 ? "work order" : "work orders";
+  return `${name} will no longer be selectable for new work orders. It still has ${openCount} open ${plural} — they'll keep it as-is unless you reassign them.`;
+}
+
 export function VendorDeactivationDialog({
   target,
   isLoading,
@@ -36,16 +47,16 @@ export function VendorDeactivationDialog({
   onClose,
   onConfirm,
 }: VendorDeactivationDialogProps) {
-  const hasBlockingImpact = Boolean(impact && !impact.canDeactivate);
+  const openWorkOrders = impact?.openWorkOrders ?? [];
+  const hasOpenWorkOrders = openWorkOrders.length > 0;
 
   return (
     <Dialog open={Boolean(target)} onClose={isSaving ? undefined : onClose}>
-      <DialogTitle>Deactivate Vendor</DialogTitle>
+      <DialogTitle>Deactivate this vendor?</DialogTitle>
       <DialogContent>
         <Stack spacing={2}>
           <DialogContentText>
-            Deactivate &quot;{target?.companyName}&quot;? Existing work-order and audit history will
-            be preserved.
+            {deactivationMessage(target?.companyName, openWorkOrders.length)}
           </DialogContentText>
 
           {isLoading && (
@@ -63,19 +74,13 @@ export function VendorDeactivationDialog({
             </Alert>
           )}
 
-          {impact != null && !isLoading && !impact.canDeactivate && (
-            <Alert severity="error">
-              This vendor cannot be deactivated because it still has open work orders.
-            </Alert>
-          )}
-
-          {impact != null && impact.openWorkOrders.length > 0 && (
+          {hasOpenWorkOrders && (
             <Box>
               <Typography variant="subtitle2" className="font-semibold uppercase">
-                Open work orders ({impact.openWorkOrders.length})
+                Open work orders ({openWorkOrders.length})
               </Typography>
               <List dense sx={{ mt: 0.5 }}>
-                {impact.openWorkOrders.map((wo) => (
+                {openWorkOrders.map((wo) => (
                   <ListItem
                     key={String(wo.workOrderId)}
                     sx={{ px: 0, py: 0.25 }}
@@ -88,11 +93,11 @@ export function VendorDeactivationDialog({
                     }
                   >
                     <Stack>
-                      <Typography variant="body2">
+                      <Link component={RouterLink} to={`/workorders/${wo.workOrderId}`}>
                         {wo.workOrderNumber
                           ? `${wo.workOrderNumber} — ${wo.workOrderTitle || "Untitled"}`
                           : wo.workOrderTitle || `Work order ${wo.workOrderId}`}
-                      </Typography>
+                      </Link>
                       {Boolean(wo.status) && (
                         <Typography variant="caption" sx={{ color: "text.secondary" }}>
                           {wo.status}
@@ -113,12 +118,12 @@ export function VendorDeactivationDialog({
           Cancel
         </Button>
         <Button
-          color="error"
+          color={hasOpenWorkOrders ? "warning" : "error"}
           variant="contained"
           onClick={onConfirm}
-          disabled={isSaving || isLoading || hasBlockingImpact || Boolean(impactError)}
+          disabled={isSaving || isLoading || Boolean(impactError)}
         >
-          {isSaving ? "Deactivating..." : "Deactivate"}
+          {isSaving ? "Deactivating..." : hasOpenWorkOrders ? "Deactivate anyway" : "Deactivate"}
         </Button>
       </DialogActions>
     </Dialog>
diff --git a/src/domain/vendors/api/vendors-api.ts b/src/domain/vendors/api/vendors-api.ts
index 467a3a3b..5afbc13e 100644
--- a/src/domain/vendors/api/vendors-api.ts
+++ b/src/domain/vendors/api/vendors-api.ts
@@ -101,8 +101,11 @@ export const vendorsApi = {
     return mapVendor(handleApiResponse(data));
   },
 
-  delete: async (id: string | number): Promise<void> => {
-    await apiDelete(`${API_PATHS.rest.vendors}/${id}`);
+  // SH-254: confirmOpenWorkOrders tells the API the caller has been shown the
+  // vendor's open work orders and chose to proceed. Without it the API still blocks.
+  delete: async (id: string | number, confirmOpenWorkOrders = false): Promise<void> => {
+    const suffix = confirmOpenWorkOrders ? "?confirmOpenWorkOrders=true" : "";
+    await apiDelete(`${API_PATHS.rest.vendors}/${id}${suffix}`);
   },
 
   getDeactivationImpact: async (id: string | number): Promise<VendorDeactivationImpact> => {
diff --git a/src/domain/vendors/use-cases/use-delete-vendor.ts b/src/domain/vendors/use-cases/use-delete-vendor.ts
index 0457cc7e..17f8ae11 100644
--- a/src/domain/vendors/use-cases/use-delete-vendor.ts
+++ b/src/domain/vendors/use-cases/use-delete-vendor.ts
@@ -3,11 +3,17 @@ import { toast } from "react-toastify";
 import { vendorsApi } from "@/domain/vendors/api/vendors-api";
 import { queryKeys } from "@/infra/query-key/query-key";
 
-export function useDeleteVendor(): UseMutationResult<void, Error, string | number> {
+export interface DeleteVendorInput {
+  id: string | number;
+  confirmOpenWorkOrders?: boolean;
+}
+
+export function useDeleteVendor(): UseMutationResult<void, Error, DeleteVendorInput> {
   const queryClient = useQueryClient();
 
   return useMutation({
-    mutationFn: (id: string | number) => vendorsApi.delete(id),
+    mutationFn: ({ id, confirmOpenWorkOrders = false }: DeleteVendorInput) =>
+      vendorsApi.delete(id, confirmOpenWorkOrders),
     onSuccess: () => {
       void queryClient.invalidateQueries({ queryKey: queryKeys.vendors.all });
       toast.success("Vendor deactivated");
diff --git a/src/test/app/(protected)/vendors/vendors-list.test.tsx b/src/test/app/(protected)/vendors/vendors-list.test.tsx
index cbfa47f9..ae5a18d3 100644
--- a/src/test/app/(protected)/vendors/vendors-list.test.tsx
+++ b/src/test/app/(protected)/vendors/vendors-list.test.tsx
@@ -177,7 +177,7 @@ describe("VendorsListPage", () => {
     expect(screen.getByRole("heading", { level: 2, name: "Adam Whyte" })).toBeInTheDocument();
   });
 
-  it("blocks deactivation when the preflight reports open work orders", async () => {
+  it("offers deactivate-anyway when the preflight reports open work orders", async () => {
     setupDefaults();
     useVendorCompanyRoster.mockReturnValue({
       data: activeRoster,
@@ -213,13 +213,52 @@ describe("VendorsListPage", () => {
     await userEvent.click(screen.getByRole("switch", { name: "Active status" }));
 
     expect(
-      screen.getByText(/cannot be deactivated because it still has open work orders/),
+      screen.getByText(
+        /will no longer be selectable for new work orders\. It still has 1 open work order —/,
+      ),
     ).toBeInTheDocument();
-    expect(screen.getByText(/Boiler repair/)).toBeInTheDocument();
-    expect(screen.getByRole("button", { name: /^Deactivate$/ })).toBeDisabled();
-    expect(mutate).not.toHaveBeenCalled();
+    expect(screen.getByRole("link", { name: /Boiler repair/ })).toHaveAttribute(
+      "href",
+      "/workorders/101",
+    );
+
+    const confirm = screen.getByRole("button", { name: "Deactivate anyway" });
+    expect(confirm).toBeEnabled();
+    await userEvent.click(confirm);
+
+    expect(mutate).toHaveBeenCalledWith({ id: 1, confirmOpenWorkOrders: true }, expect.anything());
   });
 
+  it("deactivates without the confirmation flag when nothing is linked", async () => {
+    setupDefaults();
+    useVendorCompanyRoster.mockReturnValue({
+      data: activeRoster,
+      isLoading: false,
+      isError: false,
+      error: null,
+      refetch: vi.fn(),
+    });
+    useVendorDeactivationImpact.mockReturnValue({
+      data: { vendorId: 1, canDeactivate: true, openWorkOrders: [] },
+      isLoading: false,
+      error: null,
+    });
+    useVendorsList.mockImplementation((params: { isActive?: boolean; pageSize?: number }) => {
+      if (params.pageSize === 1) return result([], 1);
+      return params.isActive ? result([activeVendor], 1) : result([], 0);
+    });
+
+    renderWithProviders(<VendorsListPage />, { route: "/vendors", withAuth: false });
+
+    await userEvent.click(screen.getByRole("button", { name: "Edit vendor Gateway Plumbing" }));
+    await userEvent.click(screen.getByRole("switch", { name: "Active status" }));
+
+    expect(screen.queryByText(/It still has/)).not.toBeInTheDocument();
+    await userEvent.click(screen.getByRole("button", { name: /^Deactivate$/ }));
+
+    expect(mutate).toHaveBeenCalledWith({ id: 1, confirmOpenWorkOrders: false }, expect.anything());
+  }, 10_000);
+
   it("preserves inline edits when deactivation is cancelled", async () => {
     setupDefaults();
     useVendorCompanyRoster.mockReturnValue({
@@ -247,7 +286,7 @@ describe("VendorsListPage", () => {
     await userEvent.type(company, "Draft Company Name");
     await userEvent.click(screen.getByRole("switch", { name: "Active status" }));
     await userEvent.click(
-      within(screen.getByRole("dialog", { name: "Deactivate Vendor" })).getByRole("button", {
+      within(screen.getByRole("dialog", { name: "Deactivate this vendor?" })).getByRole("button", {
         name: "Cancel",
       }),
     );