Paneling and Trim - Imitation tile paneling joints

I bought some fiber board tile paneling for the bathroom. It is
white but the joints show as dark cracks between sheets.
Lowe's apparently don't sell, or you're are not supposed to
use, the plastic joints between sheets. They were nowhere
to be found near the paneling. What is the best way to
hide these joints?

Caulk the seams and paint some batten molding and intstall to hide the gaps. Fiber board is not a good product to use in a wet area.

I used these in a previous house because it was way better than what was there - dark wood paneling over damaged plaster - and I couldn't afford to tile. It came out looking pretty good when it was done. I tried to caulk in between the first two pieces. Didn't look good at all. That joint stood out just about as much as the plastic pieces did.

Look again for the plastic things, unless you've asked about them and they don't carry them. If they don't have them look somewhere else for them. I'm sure they're all the same regardless of who sells them. I've seen them at Menards in the back where all the paneling is in a big bucket-like thing.

Incidentally, when I did ours I wasn't sure what to do at the top where the panel met the ceiling. I ended up putting some wood molding there to hide the edge. I thought I could caulk it but the ceiling was too uneven to get a tight fit without way too much scribing and trimming. I bought paint that matched the color of the panels really well and it turned out looking very nice.

Caulking will work but it helps to be able to lay a nice bead of caulking. Otherwise painting and installing wood trim like Crocostimpy did is a good alternative.

To add another tip, if you caulk, use paintable caulk.