The base game is free to download and play.
Arc Games still describes Star Trek Online as a free-to-play MMORPG, and the official Steam, Epic, PlayStation and Xbox stores all list the base game as free.
Yes. Star Trek Online is free to download and play on PC, PlayStation and Xbox. Optional in-game purchases and paid bundles are available.
Yes. You do not have to buy the base game or pay a required monthly subscription to play.
Arc Games still describes Star Trek Online as a free-to-play MMORPG, and the official Steam, Epic, PlayStation and Xbox stores all list the base game as free.
STO originally launched as a paid subscription MMO in 2010 and changed business model less than two years later.
Use the official store or launcher for your platform.
Star Trek Online is available free on all three official PC distribution routes.
Short version: the base game is free. Pick the official download route for your platform and play; paid purchases are optional.