To get to the Lao-Thai border crossing at Chong Mek , you'll first need to cross the Mekong from Pakxe to Ban Muang Kao . Ferries leave regularly from the ferry landing at the southwestern corner of the city centre (2000K) or you can get a motorized pirogue, which departs when full (2000K) or can be hired (20,000K for up to ten people) for the trip. This service will run its course once a new bridge , under construction at the time of writing, is open to traffic. Jury-rigged jalopies whip along the forty-kilometre route from Ban Muang Kao to the border crossing (daily 8.30am-4pm), taking around forty-five mintues. These taxis can be hired (90,000K) or shared (9000K). Sawngthaews also ply the route (1hr 15min; 3000K). Drivers will accept Thai baht or kip. The expansive market that straddles the border thrives on weekends. After tipping the immigration officers to exit Laos (it's always a weekend or lunchtime as far as they are concerned), cross into Thailand to find pick-ups to Phibun Mangsahan, where you can transfer to buses to Ubon Ratchathani, with plentiful road and rail links . There are also two direct Chong Mek-to-Bangkok air-conditioned buses that leave from the market at 4pm and 5pm respectively.