Any advice for leaving the dog on the beach while going for a surf?

My 7 month golden retriever will lie on my towel when I go for a quick swim after a beach run. A surf/kite however means longer time in the water and a lot further out from shore.

Blowies, blue bottles could be a problem. Perhaps other unfriendly dog encounters also.

Council/shire laws likely prohibit leaving a dog unattended... Metro vs out of town spots?

Cheers!