family vacation; family trip
A trip or vacation taken together with one's family.
We plan to go to Hokkaido on a family trip this summer.
Memories of family trips are lifelong treasures.
家族旅行 means a family trip or vacation specifically, whereas 家族連れ more broadly describes any outing or group of family members together.
Compound of 家族 (family) and 旅行 (travel).