Arriving by 9–10 am gives you a strong chance of finding a decent sunbed at most beaches in July and August. The busiest public stretches — Slovenska Plaza in Budva, Becici, and Sutomore — can be largely occupied by mid-morning on hot weekends. Quieter options like Kamenovo or the pebble coves near Rose tend to stay less crowded even later in the day.
If you are set on a specific premium spot or a central location at Sveti Stefan area, booking a baldahin the day before is far more reliable than arriving early and hoping. For walk-up beaches, bringing a beach mat as a backup is a practical habit during the August rush.