when is the best time to visit Bangka, Belitung ?
If you like to have an island hoping experience, it's better to go by March to November because starting early December til February, the weather is bad and it's kinda risky to travel by boat or do water sport. But if you just want to enjoy the beach, avoid peak season because there will be very crowded and accommodation will be expensive.
Yes prefer to go after February, after raining season. Also if you go there, hotel will be more expensive before February. April - June is good, no high season and better you book hotel by online (will be cheaper).