The closest beach to Uranoupoli (Athos) is Ouranoupoli, just 260 m away. Within 15 km there are 15 beaches; below are the 12 closest to Uranoupoli, ordered by distance. Photos, map, reviews.
260 m from Uranoupoli

380 m from Uranoupoli

1.8 km from Uranoupoli

2.3 km from Uranoupoli

2.6 km from Uranoupoli

3.2 km from Uranoupoli

6.7 km from Uranoupoli

6.9 km from Uranoupoli

7.4 km from Uranoupoli

11.0 km from Uranoupoli

11.5 km from Uranoupoli

11.8 km from Uranoupoli

Ouranoupoli, just 260 m from Uranoupoli. The rest are listed below, ordered by distance.
Within 15 km of Uranoupoli there are 15 beaches.
Based on user reviews: Ouranoupoli (★4.5), Trypiti (★4.5), Develiki Ouranoupoli (★4.3).
The beaches are spread out around Uranoupoli. A car makes exploring much easier — local buses and taxis are limited outside peak season.
Uranoupoli is on the Athos side of Halkidiki, in northern Greece. The nearest airport is Thessaloniki (SKG); from there a car is the most convenient way to reach the Athos villages.