Something is eating my tomatoes. Help!
This looks like some type of wildlife damage but we cannot say for sure what type.
Squirrels, chipmunks, raccoons, and groundhogs are most likely to take bites from the tomatoes. They are looking for moisture. Looks like you have some type of fencing around the tomatoes to protect them. You may want to sprinkle some flour around the area and look for tracks.
There are no easy answers. Here are some suggestions.
Pick your tomatoes before they are completely ripe (at the blush stage) and let them ripen on your kitchen counter. Cover the plants with floating row cover or bags. Provide water nearby and the critter might go for the water and leave your tomatoes alone.