Fat tires have no puncture-resistant options worthy of the name. The reason is simple: Think of how heavy a thorn-resistant tube is. Now scale it up so its diameter is gigantic like a fat tire. Same deal with the tire itself. They'd be super heavy. You can purchase Tannus Armour but having done many installs of it, I'll recommend you stay away from it. Too many negatives.
With that said, I have done rather a lot of daily riding on fat tires and I've got what I'd call the secret formula for flat prevention. Secret in 2020 at least. In 2023 its pretty common:
Use FlatOut Sportsman Formula. It will seal holes up to 1/2" in size and never hardens. Has a lifespan of 10 years so thats effectively the life of the tube. It works as a tubeless sealant as well. Running tubeless with a full cargo load on my Surly Big Fat Dummy, I hit a strip of 6 discarded roofing nails and so had 6 punctures, closely spaced, at the right side of my tire. tread. Fortunately I also had an electric air pump as well. I refilled, spun the tire, rode about a block and stopped; refilled again and did so three more times, with air loss being steadily less with each fill. The sealant repaired the damage and I rode home. That was a couple of years ago and the same tire is still on the bike, although it is about worn out now.
Here is an excellent fat tire flat test. Note the Tannus vs. Flatout performance.
And here is the tool kit to run around with. Heavy emphasis on the patch kit.
In the last few months, I’ve made a few changes to my standard on-bike tool kits. Lets take a look.
talesontwowheels.com
You really, REALLY need to learn to patch tubes if you don't know how to already. Consider the cost of one tube, and then look at this pic below. 5 patches visible and it got to 7 before #8 was on a seam that could not be patched. Patches are stronger than the original tube material and cold-vulcanize to the surface, so they may as well be welded on.
