Buses take around 1.5 to 2 hours to/from Hanoi, depending on the type of bus and the route it takes. Allow 2 hours to be safe. From Hanoi, buses leave from Giap Bat (southern) bus station. As soon as you arrive you are likely to be accosted by someone asking if you want to go to Ninh Binh — they are trying to get you on their bus and there’s no harm in this, just make sure they take you to buy a ticket at the window in the ticket office before getting on the bus.
Ninh Binh’s bus station is located near the railway station, just across the bridge leading to Phat Diem, on the last section of Tran Hung Dao (Highway 1) going south towards Hue. Buses to all destinations are frequent and you’ll rarely have to wait long. If you’re not staying near the bus station, you can wait on the main road — Tran Hung Dao — and wave down a bus, but you may be stuck sitting on the floor.
Most buses to Hanoi terminate at Giap Bat bus station, although some go to My Dinh. Either is a bit of a trek from Hoan Kiem.
Two best places to see in Ninh Binh: