The closest beach to Porto Koufo (Sithonia) is Porto Koufo, just 300 m away. Within 15 km there are 28 beaches; below are the 12 closest to Porto Koufo, ordered by distance. Photos, map, reviews.
300 m from Porto Koufo

1.9 km from Porto Koufo

2.8 km from Porto Koufo

3.2 km from Porto Koufo

4.4 km from Porto Koufo

5.4 km from Porto Koufo

5.7 km from Porto Koufo

6.3 km from Porto Koufo

6.3 km from Porto Koufo

6.6 km from Porto Koufo

6.7 km from Porto Koufo

6.8 km from Porto Koufo

Porto Koufo, just 300 m from Porto Koufo. The rest are listed below, ordered by distance.
Within 15 km of Porto Koufo there are 28 beaches, with 69 across Sithonia in total.
Based on user reviews: Aretes Beach (★5.0), Toroni Beach (★3.8), Destinika Nudist Beach (★3.8).
The beaches are spread out around Porto Koufo. A car makes exploring much easier — local buses and taxis are limited outside peak season.
Porto Koufo is on the Sithonia side of Halkidiki, in northern Greece. The nearest airport is Thessaloniki (SKG); from there a car is the most convenient way to reach the Sithonia villages.