You will have to go into Oceanside. The ups store on base charge 25.00 to have a package deceived if you don't a post box there.
Oceanside Post Offices are probably closest. There are USPS offices on Camp Pendleton, but I am not sure where they are located and whether they offer General Delivery service. BTW, the Del Mar Beach "resort" on Camp Pendleton is *not* close to Del Mar, CA. It is located on Camp Pendleton and eligibility for access to military installations is required.
Some active duty Marines who live in their RV'S or trailers probably have their mail delivered to a post office close to Del Mar. Search for nearest post office for convenience.
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