I've yet to find anything in Gdansk/Tricity
The Anglicans have a monthly Eucharist in Gdansk and there are various sorts of evangelical gatherings there.
Here's a link: anglicanchurch.pl
I didn't see anything on the site about Gdansk, so you'd have to contact them to check the details.
There's also: gracechurchgdansk.org which looks like an American fundamentalist organisation. There are also Polish speaking protestant churches there plus the Jehovah's Witnesses.