I am trying to help find an ideal honeymoon site for my son and his partner following their marriage next June. They are thinking Spain and want beach, sun, good food and fairly easy access to train or airport. All suggestions will be appreciated.

What time of year?
What is the budget?
Is the beach their only interest?

Sitges may suit them in all ways as it's a world-renown gay resort - about an hour from Barcelona so can visit that too.

http://gaysitges.com/

Water a balmy 72F in June:

http://www.holiday-weather.com/sitges/averages/june/

End of June. Budget not a great factor, high end but not ridiculous. They did mention Sitges but couldn't seem to find a good hotel .... that was when I stepped in and told them "I will find something perfect" and went right to Fodors.

Valencia, Malaga...

Have you checked out Calipolis or Casa Vilella in Sitges?

San Sebastián, the culinary capital of Spain if not all of Europe, some of the finest city beaches on the continent, and one of the most beautiful cities in the country: http://www.euskoguide.com/places-bas...stian-tourism/
"Is San Sebastian the world's greatest city for foodies": http://www.telegraph.co.uk/travel/de...y-for-foodies/

Can suggest to stay in Hotel Londres, right on the famous La Concha beach promenade: https://www.hlondres.com/en/accommodation/attic

Or wonderful and fun Málaga city on the Mediterranean. Andalucía's city of cultire, one of the oldets cities in the world, worl class museums, fabulous both traditional and cutting edge food scene, great theaters, culture scene and nightlife. Dozens of cafés in the many plazas and tons of tapas bars in the narrow streets in the old town. https://www.lonelyplanet.com/spain/andalucia/malaga

Perhaps stay in Gran Hotel Miramar right on the Malagueta Beach. The spectacular old hotel from 1926 has recently reopened: http://www.granhotelmiramarmalaga.com/en/