Khoiyachhora Waterfall is very easy to access especially if you are from Chittagong town, but not that much difficult either if you are from Dhaka. First come to Boro Takia Bazar of Mirsarai. You can do this by leaving the Dhaka-Chittagong bus on highway. Your dropping zone will be (22°45’39.54″N, 91°34’55.56″E) which is before the Boro Takia Bazar.
From there you can start trekking for 15 minutes through the concrete road and it will lead you toward a rail crossing. The GPS coordinate of that place is (22°45’55.98″N, 91°35’33.05″E). After the rail crossing, the typical Bangladeshi country road will lead you towards the bottom of the hills (at the water stream of the waterfall).
Until reaching the water stream you can ask for help from the local villagers. Even you can hire anyone from them to enlighten you further. After reaching the water stream, just follow the trail around that, and stay beside the stream and it will automatically lead you towards the waterfall itself. The GPS coordinate of the bottom steps of the Khoiyachhora Waterfall is (22°46’9.44″N, 91°36’41.77″E).
Depending upon your walking speed it will be around 1 to 2 hours of trekking for single trip. It will require same amount of time when you’ll come back from there. So prepare yourself by doing exercise if you are not familiar with regular walking.