Upvote:2
Regarding Gdanks, as I discovered later, there are plenty of luggage lockers. It just happens that I exited through the "wrong" side of the station (via the bus terminal) where they have at most 10 lockers (and they were all full).
Additional information
On the main entrance of the station there are several lockers. It seems to be busy since most of them were full. There are more lockers downstairs though.
Upvote:2
There is a luggage storage point in the city centre https://plus.google.com/107594251083173710256/about?gl=pl&hl=pl
Upvote:4
One option is to go to a hostel and ask them. For example, Hostel Zappio (I believe that's the one I stayed in, but I'm not sure) - it shows online as having luggage storage. Yes, in theory that's for guests staying there, but I've asked shops and hostels/hotels to look after bags for me in the past, and sometimes they've done it for free, sometimes for a small fee. And if it's just a small fee, it may well be worth it for you to try.