Designed for two, with suits. To fit three, no suits. After this, the Soviet Union only flew two at a time, until some redesign years later that made room for three to fit with suits.
Soyuz 11 docked with the first real space station, Salyut-1. A year before Skylab.
https://www.armaghplanet.com/blog/soyuz-11-the-truth-about-the-salyut-1-space-disaster.html
BTW - Soyuz 1 only had one crew, Komarov. But, the plan was to launch Soyuz 2, rendezvous, and transfer one of two cosmonauts in Soyuz 2 to join Komarov in Soyuz 1 ( A reference I just read said "swap crews". If they meant that literally, that would imply Komarov would have gotten into Soyuz 2 and the original Soyuz 2 crew would have come down in Soyuz 1. Someone else can google for further clarification). But Soyuz 1 had so many problems right away that the launch of Soyuz 2 was called off.
Also, BTW, the Lunar version of Soyuz also was a two-crew ship. One would stay with it in lunar orbit, the other would transfer to a lander, undock, land, and fly back to transfer that 2nd crewman back into Soyuz.
Update -see Winston's thread about Soyuz-1. I forgot Soyuz-2 was to have had a crew of 3.
https://www.rocketryforum.com/showthread.php?126206-Soyuz-1-loss
