"seaside vacation" is correct and usable in written English.
You can use it to refer to a holiday spent near the sea or ocean, e.g. "My family and I really enjoyed our seaside vacation in Spain last summer!".
They were scheduled to board a plane on Saturday for a seaside vacation in Spain.
In the 20th century many seaside vacation cottages were built among the older fishing villages along the shore.
This week's film is "Liberté-Oléron" (2001), starring Denis Podalydès as a middle-class family man on a seaside vacation.
The play was Shaw's "You Never Can Tell," which deals with Mrs. Lanfrey Clandon, her children and "that horrid man," their father, on a seaside vacation.
Popular seaside vacation resorts include Saint-Tropez, Cannes, and Cap d'Agde on the Mediterranean, the Île de Ré and La Baule-Escoublac on the Atlantic coast, and Le Touquet on the English Channel.
Already, with Mr. Hollande only 100 days in office and on a seaside vacation, public confidence is waning in his ability to square the circle, even as the economy worsens.
The Manet family began to take seaside vacations at Boulogne-sur-Mer in 1864.
Janine had them, too, or at least flirtations, especially on their seaside vacations in Deauville.
The pace of August, normally a hot and happy month of seaside vacations and weddings in the Maghreb, has been especially frenetic this year.
In one of these cases you can see a series of elegant, lively book illustrations on the pleasures and perils of seaside vacations on the beaches of Britain.
And no seaside vacations for Mr. Kalil, thank you. "I view the harbor from my home and the kill from my office," he said, "and that's enough water for me".
