My mom (because of my nutsos brother) finally put in metal sprinkler heads.Will that work with your system? PJ

Rick, this is the only thing I could find!!?? You would think there would be more products for this.
Spikes sound good to me. You could sit out there with a paintball gun OR do like my GM did and confiscate the skateboards and if the parents object tell them when they replace your sprinkler heads they can have them back

Here is a link that might be useful: sprinkler protectors

Metal heads would just transfer the impact to the line connector, even if they made 12" which as far as I know, they don't.

The doughnuts won't work, either as they aren't high enough.

May have to "fabricate" something. Lot of extra work, unfortunately.

As for confiscating skateboards, etc., we don't even know it has been done, till we go after mail, and find the head laying on the sidewalk. Naturally, they don't even have the courtesy to admit they broke it off, when they do it.

Rick, we wound up having 2 corner split-rail fences built. It wasn't cheap, but after having to replace sprinklerheads twice, it was worth it.

I had a similar product like the O'Shield in Jac's link at my old house and they really helped. I got them about 7 years ago at a Home Depot in FT Worth in the cement block dept. for about $1 apiece.I haven't seen them at our local HD, maybe they don't carry them anymore.

Yesterday, I believe I may have observed the recent culprit. Someone in the neighborhood, has been so foolish as to buy a battery powered plastic 4 wheeler, for his small child, who can barely steer it, and has him riding it on the sidewalk, while he jogs.

Argggghhhh!

Caltrops seem a little extreme....
Hmmm....a bright orange mini cage over each one? Like a light cover thing they use to protect clocks and lights where people play basketball inside? That'd be a real pain but I can't think of anything else. Put those long,skinny nails down the holes they have to secure them on? Best I can think of sorry! PJ

Put your sprinkler heads on an "L" or elbow joint. That way when they are hit by something, a car, a skateboard, they will flex with the elbow joint instead of breaking off. You will probably have to adjust your sprinkler head lower.
Simply glue the elbow joint to the main line, where the sprinkler head is currently attached, then glue the sprinkler head to the other end.
Learned this trick in sprinkler class!
Cheap, impresses the client when their heads don't break off.
Though, of course you don't make as much on repairs...
Tally HO!

Man, I wish I'd learned that trick back in CA! Very clever. I got so darn sick of sprinkler repair I went xeriscape to avoid watering! PJ

Repairs are where the money is.
Tally HO!

Yep! All my money went to Home Depot's sprinkler dept! LOL. PJ

Old post, I know. Just started reading this forum.

I built some guards for mine out of an ABS coupling that form a little 'cage' around the head, and protect them from crushing from above:

More detail on the step-by-step install if interested.

That's pretty cool! But I must say, if concrete donuts aren't working, heads are too high. Swing joints are a good way to protect the heads by offering some (but not a lot) of joint flexibility.