If you're unable to find Worms 3D for free, consider purchasing it from official stores like:

Surprisingly, Team17 pulled it off. Released in 2003, Worms 3D was a landmark title for the series. It retained the core gameplay loop: teams of worms taking turns trying to obliterate each other using an arsenal of bizarre weaponry. However, the move to 3D added a layer of complexity that changed the strategy entirely.

Create your own team of worms, choose their names, pick their voices, and design your own flags and gravestones. Worms 3D System Requirements