Try making bath time a pleasant experience, as much as possible. Where do you bathe him? I use a sink because my boys are too nervous in a bathtub. We use the faucet spray hose for the body and a measuring cup to pour water over the head.
I talk to my boys during the bath, praising them and saying silly things, and telling them what I am doing: "Time for the shampoo to scrub a dub dub, Max in the tub."
This seems to be calming and reassuring.
I massage their bodies while working in the shampoo.
They are always happy to smell the conditioner because they know that means they are almost finished. Then I have big, warm towels to wrap them in before letting them run and do zoomies.
Finally, we have treats and hairdryer time.
Make a ritual out of the whole process and your little one will hopefully learn to tolerate the bath. You may also consider different methods of bathing --- i.e. sink vs tub, or pouring water vs. spraying water.