Here's how to patch a wetsuit.

A friend gave me this nice orange survival suit.
A coastguard station near her house threw it out because a mouse gnawed a hole in it.
They wrote "Condemned" on it which makes it extra stylish.

Here's the hole in the ankle of the suit.

I guess I'm supposed to buy eggs.

Step 1: Clean the Wound

Pick which side the patch will go on.

Cut that top surface away with the cloth layer (if any) away so it tapers down to the hole.

Here I'm using the scissors on the "instructables" leatherman ewilhelm laser-etched for me.

Wetsuits are made of neoprene rubber foam. The little bubbles in the rubber foam make it a good insulator. The bubbles are not connected to each other so it doesn't soak up water.
Old-style wetsuit material like this has thin knitted nylon cloth laminated on both sides.
It's a lot more durable than the newer suits with cloth on one or neither side.
It's also heavier, less elastic, and less warm because the outside cloth stays wet when you
get out of the water, and then your body heat has to evaporate this water.
Modern suits are a compromise between durability, elasticity, and warmth.

Most of the world's wetsuit material comes from a single factory in Thailand.

Step 2: Wound Is Properly Cleaned Up

You'll have plenty of surface area to make the patch stick.
The tapering means you won't get stress concentrations for rips to start.

Isn't it great being a nerd?

Step 3: Prepare the Skin Graft

Find a donor wetsuit with a compatible type of tissue.
Cut a patch big enough to cover the whole wound.
Cut all the fabric off one side of the patch and taper the thickness of the patch down to the edges.
If you want to get fancy leave an area of fabric in the middle the same size as the hole.
I'm not getting fancy today.

I happened to have a scrap of neoprene from the same survival suit factory I'd gotten a long time ago.
I'm from Stearns County Minnesota, which is where survival suits come from.

This particular suit used to be secret.
The code name was "George" because it looked like a guy named George who worked there.
He must have had thick ankles.
I went to the Stearns factory and asked "can I have some neoprene scraps from George?"
They said "How do you know about George?"

Step 4: Daub Glue on the Patch

I use DAP Weldwood brand Original Contact Cement.
Follow the directions.
Don't breathe the harmful fumes.
Put it on thick enough to be glossy. Let it dry long enough. Longer is better than shorter.

I made an instant foam paintbrush by ripping a chunk of foam rubber and gripping it with the pliers of my leatherman.

If you ever want to glue neoprene cloth to cloth, you need to apply several thick coats.

Step 5: Brush Glue on the Wound

Same as the patch.
Smear it on a larger area than you think is necessary.
Be extra generous with the fabric areas.
Let it dry well before sticking the patch to it.
The directions give a range of times. Use the long time.
Don't worry, If it doesn't stick well you can try again.

Step 6: Affix the Patch

Press it down hard.
Make sure all the glue molecules on both surfaces get really intimate with each other.

You're done.
Enjoy your non-perforated wetsuit.

If the patch is in a really hardworking area like the wrist, ankle, or crotch, you can sew the fabric edge of the patch to the fabric edge of the hole. Don't poke all the way through the wetsuit.
Just sew the surface cloth together.
Any kind of stitch is fine: baseball, frankenstein, whipstitch are all good methods.

Step 7: Testing

Coached by Kenny Jensen, Caglar Girit tries out the new suit while riding a human-powered ornithopter hydrofoil in the Oakland Channel. To see more details check out the Aquaskipper Instructable

The suit works great, and is good thing to have around.
Now no-one can say "but the water's too cold" or "I don't have a wetsuit"

I don't suppose I'll rely on it for my abandon-ship bag.
It would be too embarrassing to be found dead in a suit with "condemned" written on it.