diff --git a/.changeset/moody-cycles-explain.md b/.changeset/moody-cycles-explain.md
new file mode 100644
index 0000000000..7db9a6bb88
--- /dev/null
+++ b/.changeset/moody-cycles-explain.md
@@ -0,0 +1,6 @@
+---
+"@medusajs/medusa": patch
+"@medusajs/modules-sdk": patch
+---
+
+Feat/update cart product isolation
diff --git a/packages/medusa/src/api/routes/store/carts/update-cart.ts b/packages/medusa/src/api/routes/store/carts/update-cart.ts
index 8952a3ab61..5d59b65cd2 100644
--- a/packages/medusa/src/api/routes/store/carts/update-cart.ts
+++ b/packages/medusa/src/api/routes/store/carts/update-cart.ts
@@ -15,6 +15,7 @@ import { AddressPayload } from "../../../../types/common"
 import { FeatureFlagDecorators } from "../../../../utils/feature-flag-decorators"
 import { IsType } from "../../../../utils/validators/is-type"
 import { cleanResponseData } from "../../../../utils/clean-response-data"
+import IsolateProductDomainFeatureFlag from "../../../../loaders/feature-flags/isolate-product-domain"
 
 /**
  * @oas [post] /store/carts/{id}
@@ -75,14 +76,22 @@ export default async (req, res) => {
   const validated = req.validatedBody as StorePostCartsCartReq
 
   const cartService: CartService = req.scope.resolve("cartService")
+  const featureFlagRouter = req.scope.resolve("featureFlagRouter")
   const manager: EntityManager = req.scope.resolve("manager")
 
   if (req.user?.customer_id) {
     validated.customer_id = req.user.customer_id
   }
 
+  let cart
+  if (featureFlagRouter.isFeatureEnabled(IsolateProductDomainFeatureFlag.key)) {
+    cart = await retrieveCartWithIsolatedProductModule(req, id)
+  }
+
   await manager.transaction(async (transactionManager) => {
-    await cartService.withTransaction(transactionManager).update(id, validated)
+    await cartService
+      .withTransaction(transactionManager)
+      .update(cart ?? id, validated)
 
     const updated = await cartService
       .withTransaction(transactionManager)
@@ -101,9 +110,60 @@ export default async (req, res) => {
     select: defaultStoreCartFields,
     relations: defaultStoreCartRelations,
   })
+
   res.json({ cart: cleanResponseData(data, []) })
 }
 
+async function retrieveCartWithIsolatedProductModule(req, id: string) {
+  const cartService = req.scope.resolve("cartService")
+  const remoteQuery = req.scope.resolve("remoteQuery")
+
+  const relations = [
+    "items",
+    "shipping_methods",
+    "shipping_methods.shipping_option",
+    "shipping_address",
+    "billing_address",
+    "gift_cards",
+    "customer",
+    "region",
+    "payment_sessions",
+    "region.countries",
+    "discounts",
+    "discounts.rule",
+  ]
+
+  const cart = await cartService.retrieve(id, {
+    relations,
+  })
+
+  const products = await remoteQuery({
+    products: {
+      __args: {
+        id: cart.items.map((i) => i.product_id),
+      },
+      fields: ["id"],
+      variants: {
+        fields: ["id"],
+      },
+    },
+  })
+
+  const variantsMap = new Map(
+    products.flatMap((p) => p.variants).map((v) => [v.id, v])
+  )
+
+  cart.items.forEach((item) => {
+    if (!item.variant_id) {
+      return
+    }
+
+    item.variant = variantsMap.get(item.variant_id)
+  })
+
+  return cart
+}
+
 class GiftCard {
   @IsString()
   code: string
diff --git a/packages/medusa/src/services/cart.ts b/packages/medusa/src/services/cart.ts
index 7f1a0f596a..fdbcc5642b 100644
--- a/packages/medusa/src/services/cart.ts
+++ b/packages/medusa/src/services/cart.ts
@@ -1,10 +1,10 @@
 import { FlagRouter } from "@medusajs/utils"
 import { isEmpty, isEqual } from "lodash"
-import { MedusaError, isDefined } from "medusa-core-utils"
+import { isDefined, MedusaError } from "medusa-core-utils"
 import { DeepPartial, EntityManager, In, IsNull, Not } from "typeorm"
 import {
-  CustomShippingOptionService,
   CustomerService,
+  CustomShippingOptionService,
   DiscountService,
   EventBusService,
   GiftCardService,
@@ -29,8 +29,8 @@ import SalesChannelFeatureFlag from "../loaders/feature-flags/sales-channels"
 import {
   Address,
   Cart,
-  CustomShippingOption,
   Customer,
+  CustomShippingOption,
   Discount,
   DiscountRule,
   DiscountRuleType,
@@ -49,9 +49,9 @@ import {
   CartCreateProps,
   CartUpdateProps,
   FilterableCartProps,
+  isCart,
   LineItemUpdate,
   LineItemValidateData,
-  isCart,
 } from "../types/cart"
 import {
   AddressPayload,
@@ -1098,7 +1098,7 @@ class CartService extends TransactionBaseService {
     }
   }
 
-  async update(cartId: string, data: CartUpdateProps): Promise<Cart> {
+  async update(cartOrId: string | Cart, data: CartUpdateProps): Promise<Cart> {
     return await this.atomicPhase_(
       async (transactionManager: EntityManager) => {
         const cartRepo = transactionManager.withRepository(this.cartRepository_)
@@ -1117,9 +1117,11 @@ class CartService extends TransactionBaseService {
           "discounts.rule",
         ]
 
-        const cart = await this.retrieve(cartId, {
-          relations,
-        })
+        const cart = !isString(cartOrId)
+          ? cartOrId
+          : await this.retrieve(cartOrId, {
+              relations,
+            })
 
         const originalCartCustomer = { ...(cart.customer ?? {}) }
         if (data.customer_id) {
diff --git a/packages/modules-sdk/src/medusa-app.ts b/packages/modules-sdk/src/medusa-app.ts
index 1678f1134c..6265c4d7f9 100644
--- a/packages/modules-sdk/src/medusa-app.ts
+++ b/packages/modules-sdk/src/medusa-app.ts
@@ -12,8 +12,8 @@ import {
 } from "@medusajs/types"
 import {
   ContainerRegistrationKeys,
-  ModulesSdkUtils,
   isObject,
+  ModulesSdkUtils,
 } from "@medusajs/utils"
 import { MODULE_PACKAGE_NAMES, Modules } from "./definitions"
 import { MedusaModule } from "./medusa-module"
@@ -69,7 +69,7 @@ export async function MedusaApp({
   modules: Record<string, LoadedModule | LoadedModule[]>
   link: RemoteLink | undefined
   query: (
-    query: string | RemoteJoinerQuery,
+    query: string | RemoteJoinerQuery | object,
     variables?: Record<string, unknown>
   ) => Promise<any>
 }> {
@@ -152,7 +152,7 @@ export async function MedusaApp({
 
   let link: RemoteLink | undefined = undefined
   let query: (
-    query: string | RemoteJoinerQuery,
+    query: string | RemoteJoinerQuery | object,
     variables?: Record<string, unknown>
   ) => Promise<any>
 
@@ -172,7 +172,7 @@ export async function MedusaApp({
     customRemoteFetchData: remoteFetchData,
   })
   query = async (
-    query: string | RemoteJoinerQuery,
+    query: string | RemoteJoinerQuery | object,
     variables?: Record<string, unknown>
   ) => {
     return await remoteQuery.query(query, variables)