Of the Atlantic beach stops within day-trip range of Rabat, Mehdia is the one with a backstory. Forty kilometres north of the capital, sitting at the mouth of the Sebou river and a ten-minute drive from Kénitra, the beach is long, open and noticeably less developed than Temara or Skhirat. The unusual thing is what surrounds it: above the river mouth on a cliff stands the ruined kasbah of Mehdia, a Portuguese fort from 1515 later held by the Spanish and the Moroccans; a few kilometres inland sits the Sidi Boughaba Ramsar lagoon, one of the most important bird-watching sites on Morocco's Atlantic flyway.

The kasbah is an open site with minimal interpretation — partly ruined ramparts, a handful of restored bastions, and a small palace at the centre — and is free to walk. Sunset on the cliff catches the stone at its best, and the same vantage gives you the river mouth, the still-working estuary fishing fleet, and the long beach running north. The fort changed hands repeatedly through the 16th and 17th centuries, which is why the architecture mixes Portuguese, Spanish and Moroccan military elements in one walled circuit.

For birding, the Sidi Boughaba reserve is a few kilometres inland off the main road between Kénitra and Mehdia, signposted as the Centre d'éducation à l'environnement Sidi Boughaba. The lagoon is best at dawn for bird activity; spring (March–April) and autumn (October–November) migration peaks bring flamingos, ibises, marbled ducks and a long list of waders. The beach itself is at its best in summer for swimming and surfing, with a few beach clubs clustered at the south end; the rest of the year it is a long windswept walk. Drive from Rabat or take the train to Kénitra (15 minutes) plus a petit-taxi for the final ten minutes; grand taxi direct from Rabat runs around 150–200 MAD one way.