diff --git a/integration-tests/http/__tests__/fixtures/order.ts b/integration-tests/http/__tests__/fixtures/order.ts
index fe8bb208c9..ff7861543b 100644
--- a/integration-tests/http/__tests__/fixtures/order.ts
+++ b/integration-tests/http/__tests__/fixtures/order.ts
@@ -1,3 +1,4 @@
+import { addShippingMethodToCartWorkflow } from "@medusajs/core-flows"
 import {
   AdminInventoryItem,
   AdminProduct,
@@ -242,15 +243,12 @@ export async function createOrderSeeder({
 
   if (!withoutShipping) {
     // Create shipping methods for each shipping option so shipping profiles of products in the cart are supported
-    await Promise.all(
-      shippingOptions.map(async (so) => {
-        await api.post(
-          `/store/carts/${cart.id}/shipping-methods`,
-          { option_id: so.id },
-          storeHeaders
-        )
-      })
-    )
+    await addShippingMethodToCartWorkflow(container).run({
+      input: {
+        cart_id: cart.id,
+        options: shippingOptions.map((so) => ({ id: so.id })),
+      },
+    })
   }
 
   const paymentCollection = (
diff --git a/integration-tests/http/__tests__/order/admin/order.spec.ts b/integration-tests/http/__tests__/order/admin/order.spec.ts
index 9636e111a3..cdb164410b 100644
--- a/integration-tests/http/__tests__/order/admin/order.spec.ts
+++ b/integration-tests/http/__tests__/order/admin/order.spec.ts
@@ -1,4 +1,5 @@
 import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
+import { AdminShippingOption } from "@medusajs/types"
 import { ModuleRegistrationName } from "@medusajs/utils"
 import {
   adminHeaders,
@@ -9,7 +10,6 @@ import {
 import { setupTaxStructure } from "../../../../modules/__tests__/fixtures"
 import { createOrderSeeder } from "../../fixtures/order"
 import { createShippingOptionSeeder } from "../../fixtures/shipping"
-import { AdminShippingOption } from "@medusajs/types"
 
 jest.setTimeout(300000)
 
@@ -980,23 +980,6 @@ medusaIntegrationTestRunner({
           .order
       })
 
-      it("should find the order querying it by number", async () => {
-        const userEmail = "tony@stark-industries.com"
-
-        const response = (
-          await api.get(`/admin/orders/?q=non-existing`, adminHeaders)
-        ).data
-
-        expect(response.orders).toHaveLength(0)
-
-        const response2 = (
-          await api.get(`/admin/orders/?fields=+email&q=@stark`, adminHeaders)
-        ).data
-
-        expect(response2.orders).toHaveLength(1)
-        expect(response2.orders[0].email).toEqual(userEmail)
-      })
-
       it("should update stock levels correctly when creating partial fulfillment on an order", async () => {
         const orderItemId = order.items.find(
           (i) => i.variant_id === productOverride3.variants[0].id
diff --git a/packages/core/core-flows/src/cart/workflows/add-shipping-method-to-cart.ts b/packages/core/core-flows/src/cart/workflows/add-shipping-method-to-cart.ts
index 60d194919f..a9a0d539e7 100644
--- a/packages/core/core-flows/src/cart/workflows/add-shipping-method-to-cart.ts
+++ b/packages/core/core-flows/src/cart/workflows/add-shipping-method-to-cart.ts
@@ -7,8 +7,10 @@ import {
   WorkflowData,
   WorkflowResponse,
 } from "@medusajs/framework/workflows-sdk"
+import { AdditionalData } from "@medusajs/types"
 import { emitEventStep } from "../../common/steps/emit-event"
 import { useRemoteQueryStep } from "../../common/steps/use-remote-query"
+import { acquireLockStep, releaseLockStep } from "../../locking"
 import {
   addShippingMethodToCartStep,
   removeShippingMethodFromCartStep,
@@ -20,7 +22,6 @@ import { validateCartShippingOptionsPriceStep } from "../steps/validate-shipping
 import { cartFieldsForRefreshSteps } from "../utils/fields"
 import { listShippingOptionsForCartWithPricingWorkflow } from "./list-shipping-options-for-cart-with-pricing"
 import { refreshCartItemsWorkflow } from "./refresh-cart-items"
-import { AdditionalData } from "@medusajs/types"
 
 /**
  * The data to add a shipping method to a cart.
@@ -81,7 +82,16 @@ export const addShippingMethodToCartWorkflowId = "add-shipping-method-to-cart"
  */
 export const addShippingMethodToCartWorkflow = createWorkflow(
   addShippingMethodToCartWorkflowId,
-  (input: WorkflowData<AddShippingMethodToCartWorkflowInput & AdditionalData>) => {
+  (
+    input: WorkflowData<AddShippingMethodToCartWorkflowInput & AdditionalData>
+  ) => {
+    acquireLockStep({
+      key: input.cart_id,
+      timeout: 2,
+      ttl: 10,
+      skipOnSubWorkflow: true,
+    })
+    
     const cart = useRemoteQueryStep({
       entry_point: "cart",
       fields: cartFieldsForRefreshSteps,
@@ -193,17 +203,28 @@ export const addShippingMethodToCartWorkflow = createWorkflow(
       }),
       addShippingMethodToCartStep({
         shipping_methods: shippingMethodInput,
-      }),
-      emitEventStep({
-        eventName: CartWorkflowEvents.UPDATED,
-        data: { id: input.cart_id },
       })
     )
 
     refreshCartItemsWorkflow.runAsStep({
-      input: { cart_id: cart.id, shipping_methods: createdShippingMethods, additional_data: input.additional_data },
+      input: {
+        cart_id: cart.id,
+        shipping_methods: createdShippingMethods,
+        additional_data: input.additional_data,
+      },
     })
 
+    parallelize(
+      emitEventStep({
+        eventName: CartWorkflowEvents.UPDATED,
+        data: { id: input.cart_id },
+      }),
+      releaseLockStep({
+        key: cart.id,
+        skipOnSubWorkflow: true,
+      })
+    )
+
     return new WorkflowResponse(void 0, {
       hooks: [validate],
     })
diff --git a/packages/core/core-flows/src/cart/workflows/update-tax-lines.ts b/packages/core/core-flows/src/cart/workflows/update-tax-lines.ts
index 6854c3ce68..d8052d8311 100644
--- a/packages/core/core-flows/src/cart/workflows/update-tax-lines.ts
+++ b/packages/core/core-flows/src/cart/workflows/update-tax-lines.ts
@@ -9,6 +9,7 @@ import {
   when,
 } from "@medusajs/framework/workflows-sdk"
 import { useRemoteQueryStep } from "../../common"
+import { acquireLockStep, releaseLockStep } from "../../locking"
 import { getItemTaxLinesStep } from "../../tax/steps/get-item-tax-lines"
 import { setTaxLinesForItemsStep } from "../steps"
 
@@ -139,6 +140,13 @@ export const updateTaxLinesWorkflow = createWorkflow(
       return input.cart ?? fetchCart
     })
 
+    acquireLockStep({
+      key: cart.id,
+      timeout: 2,
+      ttl: 10,
+      skipOnSubWorkflow: true,
+    })
+
     const taxLineItems = getItemTaxLinesStep(
       transform({ input, cart }, (data) => ({
         orderOrCart: data.cart,
@@ -153,5 +161,10 @@ export const updateTaxLinesWorkflow = createWorkflow(
       item_tax_lines: taxLineItems.lineItemTaxLines,
       shipping_tax_lines: taxLineItems.shippingMethodsTaxLines,
     })
+
+    releaseLockStep({
+      key: cart.id,
+      skipOnSubWorkflow: true,
+    })
   }
 )