Buses travel irregularly and infrequently between Rach Gia and Hon Chong (referred to as Kien Luong district on schedules). When they do, they depart from Rach Gia's central bus station and reach Hon Chong just over two hours later, pulling up in front of the grotto. When we inquired about bus schedule to Hon Chong in Ha Tien and Rach Gia, in both cases we were told there wasn’t a bus that day and to do the following:
The more convenient way is to catch the bus or minibus running between Rach Gia and Ha Tien and tell the driver you're heading to Hon Chong. You'll be dropped at Ba Hon, at a small market town on the main highway 15 kilometres to Hon Chong. A xe om will happily take you the rest of the way.
Rach Gia to Ha Tien: Mai Linh express has an air-con minibus departing hourly from 04:40-20:15. Costs 60,000 dong. Local bus departs every 30-60 minutes from 03:00-20:00. Costs 50,000 dong and leaves when there are enough passengers.
Mai Linh Express runs from Ha Tien to Rach Gia, hourly departures starting at 04:30 until 20:15. Cost is 60,000 dong and takes 2.5 hours. Local bus departs hourly from 04:00 until 11:00. Costs 43,000 dong and leaves when there are enough passengers.
If you’re headed to Hon Chong, it’s worth inquiring if there’s a direct bus running but don’t count on it.
For those who want to drive a motorbike or hire a xe om motorbike taxi from Ha Tien, the condition of the road is dreadful. It is semi-scenic, with parts where the road skirts the water’s edge and a few bridges that give you an interesting photo of gritty villages that line narrow canals emptying out to the sea. There are also karst popping in the middle of fields – and unsightly cement factories gouging it for gravel. From Ha Tien, we hired a motorbike taxi for a full day round trip journey to Hon Chong for 400,000 dong. A one-way journey should be half of that.