楽しそうだ

looks fun; seems to be having fun

→ 楽しい
phrase Common #5,291
looks fun; seems to be having fun Used to describe how something or someone appears, rather than stating it as a fact. The plain ending だ is informal.
JA: 兄さんは大学で楽しそうだ。
EN: My older brother seems to be having fun at university.

楽しそうだね

That looks fun.

— Demon Slayer -Kimetsu no Yaiba- The Movie: Mugen Train (2020)

彼は孫と一緒のときが一番楽しそうだ。

He seems happiest when he's with his grandchildren.

いやひどく楽しそうだでいやこれは生まれつきでの

Well, you look awfully happy. No, I was born this way.

— 七人の侍 (1954)

彼はとても楽しそうだ。

He looks like he’s having a great time.

今日は随分と楽しそうだね。

You seem to be having a lot of fun today.

みんな楽しそうだの

Everyone looks like they're having fun.

— 七人の侍 (1954)

ピクニックみたいで楽しそうだ

It looks like a picnic—sounds like fun.

— レベッカ (1940)

毎朝とても楽しそうだけど。

You seem to be having a lot of fun every morning, though.

楽しそうだ

That looks fun.

— アバウト・タイム ~愛おしい時間について~ (2013)

ジェーンは楽しそうだ。

Jane looks like she's having fun.