diff --git a/src/app/activities/[activity-id]/start/page.tsx b/src/app/activities/[activity-id]/start/page.tsx
new file mode 100644
index 0000000..db68e51
--- /dev/null
+++ b/src/app/activities/[activity-id]/start/page.tsx
@@ -0,0 +1,45 @@
+import BasicLayout from "~/components/ui/BasicLayout";
+import { Textarea } from "~/components/ui/textarea";
+import { getActivity } from "~/models/activity";
+
+export default function ActivitiesStartPage({
+  params,
+}: {
+  params: { "activity-id": string };
+}) {
+  return (
+    <BasicLayout>
+      <div className="flex flex-col items-center w-full gap-y-4">
+        <Timer />
+        <Editor activityId={params["activity-id"]} />
+      </div>
+    </BasicLayout>
+  );
+}
+
+function Timer() {
+  return (
+    <>
+      00:00:00
+      <hr className="text-gray-500 w-full" />
+    </>
+  );
+}
+
+async function Editor({ activityId }: { activityId: string }) {
+  if (!activityId) {
+    return "존재하지 않는 활동이에요!";
+  }
+
+  const activity = await getActivity({ activityId });
+
+  return (
+    <section className="w-full">
+      <div className="pb-4">
+        <h1 className="font-bold">{activity.name}</h1>
+        <p className="text-sm text-gray-500">{activity.description}</p>
+      </div>
+      <Textarea autoFocus className="h-[80vh]" />
+    </section>
+  );
+}
diff --git a/src/app/activities/features/ListCard.tsx b/src/app/activities/features/ListCard.tsx
index f19bfde..e902e5a 100644
--- a/src/app/activities/features/ListCard.tsx
+++ b/src/app/activities/features/ListCard.tsx
@@ -7,7 +7,7 @@ import {
   CardTitle,
 } from "~/components/ui/card";
 import PlayButton from "./PlayButton";
-import type { Activity } from "~/models/activity";
+import { type Activity } from "~/models/activity";
 
 export default function ListCard({ activity }: { activity: Activity }) {
   return (
@@ -16,9 +16,9 @@ export default function ListCard({ activity }: { activity: Activity }) {
         <CardTitle>{activity.name}</CardTitle>
         <CardDescription>{activity.description}</CardDescription>
       </CardHeader>
-      <CardContent></CardContent>
+      <CardContent />
       <CardFooter className="justify-end">
-        <PlayButton />
+        <PlayButton activity={activity} />
       </CardFooter>
     </Card>
   );
diff --git a/src/app/activities/features/PlayButton.tsx b/src/app/activities/features/PlayButton.tsx
index ba26ac0..b63913c 100644
--- a/src/app/activities/features/PlayButton.tsx
+++ b/src/app/activities/features/PlayButton.tsx
@@ -1,9 +1,28 @@
+"use client";
+
+import { useRouter } from "next/navigation";
+import React from "react";
 import { PlayIcon } from "~/components/icons";
 import { Button } from "~/components/ui/button";
+import { Activity, startActivity } from "~/models/activity";
+
+export default function PlayButton(
+  props: React.ComponentPropsWithoutRef<"button"> & { activity: Activity },
+) {
+  const { activity, ...rest } = props;
+
+  const router = useRouter();
+
+  async function handleStartActivity() {
+    await startActivity({
+      activity: { ...activity, started_at: new Date().getTime() },
+    });
+
+    router.push(`/activities/${activity.id}/start`);
+  }
 
-export default function PlayButton() {
   return (
-    <Button>
+    <Button {...rest} onClick={handleStartActivity}>
       <PlayIcon />
     </Button>
   );
diff --git a/src/app/page.tsx b/src/app/page.tsx
index b4e2062..a79611b 100644
--- a/src/app/page.tsx
+++ b/src/app/page.tsx
@@ -1,15 +1,16 @@
 import AddButton from "~/app/activities/features/AddButton";
 import AcgivityList from "./activities/widgets/ActivityList";
+import BasicLayout from "~/components/ui/BasicLayout";
 
 export default async function HomePage() {
   return (
-    <main className="flex max-w-96 m-auto min-h-screen flex-col items-center justify-between p-8">
+    <BasicLayout>
       <div className="flex flex-col items-center w-full gap-y-4">
         00:00:00
         <hr className="text-gray-500 w-full" />
         <AddButton />
         <AcgivityList />
       </div>
-    </main>
+    </BasicLayout>
   );
 }
diff --git a/src/components/ui/BasicLayout.tsx b/src/components/ui/BasicLayout.tsx
new file mode 100644
index 0000000..342080c
--- /dev/null
+++ b/src/components/ui/BasicLayout.tsx
@@ -0,0 +1,13 @@
+import React from "react";
+
+export default function BasicLayout({
+  children,
+}: {
+  children: React.ReactNode;
+}) {
+  return (
+    <main className="flex max-w-96 m-auto min-h-screen flex-col items-center justify-between p-8">
+      {children}
+    </main>
+  );
+}
diff --git a/src/components/ui/textarea.tsx b/src/components/ui/textarea.tsx
new file mode 100644
index 0000000..44f6dc0
--- /dev/null
+++ b/src/components/ui/textarea.tsx
@@ -0,0 +1,24 @@
+import * as React from "react"
+
+import { cn } from "~/lib/utils"
+
+export interface TextareaProps
+  extends React.TextareaHTMLAttributes<HTMLTextAreaElement> {}
+
+const Textarea = React.forwardRef<HTMLTextAreaElement, TextareaProps>(
+  ({ className, ...props }, ref) => {
+    return (
+      <textarea
+        className={cn(
+          "flex min-h-[60px] w-full rounded-md border border-input bg-transparent px-3 py-2 text-sm shadow-sm placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:cursor-not-allowed disabled:opacity-50",
+          className
+        )}
+        ref={ref}
+        {...props}
+      />
+    )
+  }
+)
+Textarea.displayName = "Textarea"
+
+export { Textarea }
diff --git a/src/mocks/http.ts b/src/mocks/http.ts
index 8e5c182..b3b32fd 100644
--- a/src/mocks/http.ts
+++ b/src/mocks/http.ts
@@ -1,5 +1,6 @@
 import express from "express";
 import cors from "cors";
+import { Activity } from "~/models/activity";
 
 const app = express();
 const port = 9090;
@@ -13,13 +14,13 @@ const genId = () => {
   count = (count + 1) % Number.MAX_SAFE_INTEGER;
   return count.toString();
 };
-
-const data = {
+const data: { activities: Activity[] } = {
   activities: [
     {
       id: "0",
       name: "사이드 프로젝트/giroker",
       description: "시간단위로 기록하는 프로젝트",
+      started_at: -1,
     },
   ],
 };
@@ -30,11 +31,27 @@ const PATHS = {
 
 app.listen(port, () => console.log(`Mock server is running on port: ${port}`));
 
+app.get(PATHS.activities + "/:activity_id", (req, res) => {
+  const id = req.params["activity_id"];
+  const activity = data.activities.find((activity) => activity.id === id);
+
+  res.json({ data: activity });
+});
+
 app.get(PATHS.activities, (_, res) => {
   res.json({ data });
 });
 
 app.post(PATHS.activities, (req, res) => {
-  data.activities.unshift({ id: genId(), ...req.body });
+  data.activities.unshift({ id: genId(), started_at: -1, ...req.body });
   res.status(201).end();
 });
+
+app.post(PATHS.activities + "/:activity_id/start", (req, res) => {
+  const id = req.params["activity_id"];
+  const index = data.activities.findIndex((activity) => activity.id === id);
+
+  data.activities[index] = { ...req.body };
+
+  res.end();
+});
diff --git a/src/models/activity.ts b/src/models/activity.ts
index 604de99..9aeaba6 100644
--- a/src/models/activity.ts
+++ b/src/models/activity.ts
@@ -5,6 +5,7 @@ type Activity = {
   id: string;
   name: string;
   description: string;
+  started_at: number;
 };
 
 export const ACTIVITES = "activities";
@@ -19,6 +20,18 @@ const activitySchema = z.object({
   description: z.string().max(80, { message: "80자 이하로 설정해주세요" }),
 });
 
+async function getActivity({
+  activityId,
+}: {
+  activityId: Activity["id"];
+}): Promise<Activity> {
+  const result = await fetch(`${API_ENDPOINT}/${ACTIVITES}/${activityId}`, {
+    cache: "no-store",
+  }).then((d) => d.json());
+
+  return result.data;
+}
+
 async function getActivities(): Promise<Activity[]> {
   const result = await fetch(`${API_ENDPOINT}/${ACTIVITES}`, {
     cache: "no-store",
@@ -29,7 +42,6 @@ async function getActivities(): Promise<Activity[]> {
 
 async function createActivity({ body }: { body: Omit<Activity, "id"> }) {
   await fetch(`${API_ENDPOINT}/${ACTIVITES}`, {
-    cache: "no-store",
     method: "post",
     headers: {
       Accept: "application/json",
@@ -39,10 +51,23 @@ async function createActivity({ body }: { body: Omit<Activity, "id"> }) {
   });
 }
 
+async function startActivity({ activity }: { activity: Activity }) {
+  await fetch(`${API_ENDPOINT}/${ACTIVITES}/${activity.id}/start`, {
+    method: "post",
+    headers: {
+      Accept: "application/json",
+      "Content-Type": "application/json",
+    },
+    body: JSON.stringify(activity),
+  });
+}
+
 export {
   type Activity,
   type ActivitySchema,
   activitySchema,
-  createActivity,
+  getActivity,
   getActivities,
+  createActivity,
+  startActivity,
 };