ができたら

if/when … is ready or possible

→ が
phrase Uncommon #18,924
if/when … is ready or possible できたら is the conditional form of できる. With nouns, it often means “when … is ready” or “when … becomes available”; with an action, it can mean “if … can be done.”
JA: 用意ができたら出発しましょう。
EN: Let’s leave when everything is ready.

夕飯の支度ができたら、呼ぶよ。

I’ll call you when dinner’s ready.

子どもができたら分かるよ。

You’ll understand once you have kids.

用意ができたらすぐ、電話してね。

Call me as soon as you're ready.

あなたとあのレストランで食事ができたらよかったのに。

I wish I could have had a meal with you at that restaurant.

支度ができたら行きましょう。

Let's go once you're ready.

余裕ができたらすぐにでも新しい車を買うつもりです。

As soon as I can afford it, I plan to buy a new car.

箱から出してすぐにこれをやり遂げることができたら--ああなんてことだ

If I could accomplish this right out of the box—oh my goodness.

— ウィキッド ふたりの魔女 (2024)

子どもができたら、分かるさ。

Once you have kids, you'll understand.

腹ができたら

Once it’s ready,

— Sanjuro (1962)

用意ができたら声かけて。

Let me know when you're ready.