Do the bear lockers come with a latch attached? Or do you have to b.y.o lock to secure them?

There are two types. One is a hasp type lock as mentioned above. Those are on the wooden bear boxes. There are also metal boxes that have a recessed latch. If you are concerned about two legged bears then yes perhaps a lock for the wooden box may be necessary. According to park personel, raccoons have figured out how to open the wooden boxes. We did not experience any intrusion.

There is a tab that gets turned but bring a padlock if you plan to leave it for a while