Doai Station is unusual in that it has two single side platforms, one of which is elevated, and the other is located underground within the Shin-Shimizu Tunnel. The station is unattended. The underground platform for the northbound trains (to Echigo-Yuzawa and Nagaoka) is located 70 metres (230 ft) underground, in the middle of the 13,490-metre (44,260 ft) long Shin-Shimizu Tunnel. It takes 10 minutes to walk the 486 steps from the ticket gate to the platform. The above-ground platform for the southbound trains (to Minakami) is at ground level. The climb up the steps from the underground platform features at the start of the novel, NHK dramatization and movie versions of Climber's High by Hideo Yokoyama.