Sungailiat is a relaxed coastal town about 30 km north of Pangkalpinang, and the best base if your main goal is the beaches. It has its own small-town character — a lively morning market, seafood restaurants, the usual Indonesian street life — without the traffic and commercial bustle of the capital. Most of the better beach resorts (Tanjung Pesona, Pantai Matras, Parai Tenggiri) are within 15 minutes of the town centre.
Staying in Sungailiat rather than Pangkalpinang makes sense if you're here primarily for the coast. The town has enough accommodation options at various price points, and the beach road north of town is easy to navigate by motorbike. It's quieter than Pangkalpinang, friendlier to slow-paced wandering, and well positioned for exploring the northern half of the island.