For families, shallow water and a gentle entry into the sea matter most — and Velika Plaza near Ulcinj is Montenegro's top pick on both counts. It's a long, sandy, south-facing beach where the water stays shallow for a good distance from shore, making it safe and fun for small children.
Becici, just south of Budva, is another family favourite: it's a Blue Flag beach with organised facilities, sunbed rentals, and relatively calm water. The beaches at Petrovac — particularly Lucice — have a sheltered bay feel and tend to be calmer than the open Adriatic-facing strips. Sutomore near Bar is popular with local families and offers good amenities without the premium prices of Budva.
July and August are the peak months and beaches get busy. For a more relaxed family visit with plenty of space, aim for the second half of June or the first two weeks of September when the sea is still warm (around 24–25°C) but crowds are noticeably thinner.