Took Gymdog to Cornwall over half term and he went to a beach for the first time (well, first time since I've had him).
He LOVED it. We found a perfect starter beach for him, small, shingly, very few people or other dogs. Initially all he wanted to do was chase stones in the shallows which was fine and seemed like great exercise.
Then he started something else. With his paws he would feel out a large rock half-submerged in the sand under a foot or two of water. He then dug and dug at the rock and moving backwards pulled it right up to the shoreline. These rocks were HUGE! Massive things - bigger than his head. He would then attempt to fit the massive rock in his jaws, take it carefully right up the beach, drop it, immediately lose interest and go back and do it all over again. The zillions of pebbles and rocks actually on the beach were of no interest - only those monsters half submerged in the sand and under the water.
After a while I realised Gymdog could end up having no teeth left at the end of the holiday and tried either to distract him or help him carry the ludicrously large boulders. He wasn't having any of it, he was clearly on a beach clearing mission. His claws are nicely filed though!
So does your dog have any beach-specific behaviours?
My JRT hates water. So he scampers about the beach looking for seagull shit to roll in or unpleasant, long dead stuff to investigate. He gets particularly bothered if I swim or paddle because he can't decide whether to protect me from the sea (which he views as extremely untrustworthy) or keep his dainty paws dry.
He also spends quite a while giving horrified looks to sensible dogs who enjoy a swim.
You've reminded me of the unfortunate fondness that my JRT had for weeing on bags that people had innocently put down on their beachtowels. The day that he neatly pissed in someone's tasteful wicket basket was one I'd rather not see repeated.
Fortunately there were no picnickers at all over half term so no wee-ing accidents. Tintagel High Street on the other hand - oh dear oh dear. Gymdog had never walked down a high street before and never will again if I have anything to do with it..
Our dogs (lab and lab-pointer cross) love running, swimming, chasing sticks, and finding stinky things to roll in. Ddog2's piece de resistance was finding and rolling in half a dead, runny, manky seal. I have never smelled anything so vile. She had to be shampooed in the garden twice, before she was fit to be allowed indoors, and even then, she needed another shower to get rid of the lingering stench!
We don't know yet as we've only had him a couple of weeks and are yet to take him to a beach. Being a lab, we're still trying to teach him that he can't just run at any old dog as if they were long list old buddies. so far he's not getting it