Activities a source says happen here, in this window.
Cat Ba Island · Oct–AprMotorbike loopRoads get dangerously slippery after rain, so if you are not an experienced rider take a taxi in wet weather. The road up to Pháo đài Thần Công is steep and winding. The last few km into Việt Hải village are gravel. Avoid riding unfamiliar roads after dark.
Just ended: Fishing · Cat Ba Island (May–Aug); Snorkelling · Phu Quy Island (Mar–Aug); Freediving · Phu Quy Island (Mar–Sep) — see you next season.