We need a little more information to figure out the cause... where on the fruit do these happen? Do they look like the skin simply split, or like someone stuck a knife into them? How big are the fruit when this happens?

If you're able to post a picture, that would help enormously.

--Alison

The slits look like a knife was stuck in them only very shallow and increasing in size later. Later they seem to turn into more of a small cavity, or even somewhat hole like. I've seen them in small fruit, maybe a couple inches in diameter. Thank you. Sorry I've been away so long after my post. I sure need to get on top of this.

With something like that, I tend to suspect birds, but you didn't mention whether these were ripe or green fruit. Small birds have small beaks, which might account for the size of the initial holes, then they often use that same hole to eat more. I've seen punctures from hummingbird beaks before, and those are truly tiny.

If they're green fruit, I have no idea, unless they're simply splitting from uneven water. Very few vertebrates attack unripe fruit.

--Alison

Growth cracks maybe? I've been looking this up as I am seeing the same thing with mine.

These are not cracks, more like shallow slits that progressively worsen and become a crater or hole and ruin the tomato. The slits on the young green fruit seemed to have slowed down, maybe even stopped.