está en su cuarto

is in his or her room

→ estar
phrase Rare #35,116
is in his or her room Su can mean his, her, or their, depending on context.
SP: Mi hermana está en su cuarto.
EN: My sister is in her room.

Creo que está en su cuarto.

I think he's in his room.

— El sacrificio (1986)

Siempre está en su cuarto.

He's always in his room.

— Realmente amor (2003)

No, no está en su cuarto.

No, he's not in his room.

— Retrato de una mujer en llamas (2019)

Gwen no está en su cuarto.

Gwen isn't in her room.

— Teléfono negro 2 (2025)

Tom está en su cuarto, haciendo una maleta.

Tom is in his room, packing a suitcase.

Está en su cuarto y no quiere salir.

She's in her room and doesn't want to come out.

— Porco Rosso (1992)

La niña está en su cuarto.

The girl is in her room.

— TÁR (2022)

Está en su cuarto.

He is in his room.