YOU SAID:

My grandkids are on their way.

INTO JAPANESE

私の孫たちは向かっています。

BACK INTO ENGLISH

My grandchildren are on their way.

INTO JAPANESE

孫たちが向かっています。

BACK INTO ENGLISH

Grandchildren are on their way.

INTO JAPANESE

孫たちが出発中です。

BACK INTO ENGLISH

Grandchildren are leaving.

INTO JAPANESE

孫たちが去っていきます。

BACK INTO ENGLISH

Grandchildren are leaving.