Puerto de la Duquesa, 328 berths under an 18th-century fort

The port was built as a destination rather than grown from one. Where Torreguadiaro and Manilva pueblo each existed before anyone drew a masterplan, Duquesa is the plan: a basin cut into the shore, quays lined with low blocks, and a rank of restaurants facing the water. It sits between the coastal town of Sabinillas and the small settlement of El Castillo, all three inside the municipality of Manilva. What gives it a longer history than the buildings suggest is what it was built next to — an 18th-century fort and, under the ground beside it, a Roman site.

The stock is almost entirely apartments, and it is unusually legible. Quayside blocks hold one, two and three bedroom flats above the commercial arcade, the older ones dating from the port's first decades and now generating a steady flow of refurbishment projects. Behind them, terraced and semi-detached complexes step back from the water with communal pools and gardens. Prices and character change with each row back from the quay. Townhouses exist; villas essentially do not. Underground parking is common and worth confirming, because on-street space here disappears in July.

Life is set by the port and by a foreign community that has been here long enough to be permanent rather than seasonal. The arcade round the water carries the restaurants, the bars and most of the year-round social life; the beach and the supermarkets are in Sabinillas, a short walk or a very short drive north. Golf is close and much of the resident population plays. In February a real proportion of the businesses stay open, because the residents are not going anywhere, and the quay is used for dog walking and reading the paper rather than for tourism.

The caveats are the ones any marina carries and a couple that are specific. Berths and apartments are separate assets: a flat on the water gives no automatic right to moor in front of it. The commercial arcade means noise, and a flat above a terrace is not the same product as one two rows back. Building ages now put lifts, waterproofing and the underground car park into major-works territory in some communities. Against that, this is the most affordable genuine marina address on the corridor and it lets well for longer than a beach flat does. Buyers here are usually buying a place to use rather than an asset to hold, which keeps turnover healthy and the market broad.

A single designed idea, repeated and then extended. The quayside is low-rise Mediterranean pastiche: rendered façades in ochre and white, arcaded ground floors carrying shops and restaurants, shallow tiled roofs, and balconies squared to the water. Behind that first line the scale drops to terraced and semi-detached houses around communal pools. The oldest blocks belong to the port's first decades and now supply most of the refurbishment stock — original bathrooms, original wiring, good bones. Later phases stepped inland with better insulation and underground parking. The one genuinely old building is the fort, and nothing was built to match it.

The quay is the high street. Coffee, a haircut, a chandler, dinner and a bar all sit on the same circuit, and most residents do the whole of it on foot. The supermarket run and the beach are in Sabinillas, minutes north. Golf takes up a large share of the week for a large share of the population. February keeps a working set of restaurants open because the community is resident rather than visiting, though the terraces thin. From late June the arcade becomes loud in the evenings, and that is audible three floors up.

It suits an owner who wants a waterfront they can walk, English spoken on the quay, low running costs and a flat that lets outside July and August as well as inside them. Boat owners and golfers are the two obvious groups. It does not suit a buyer looking for privacy, a garden, a plot, a quiet terrace above a restaurant arcade, or the discretion of a gated estate; nor anyone who assumes that buying on the water includes somewhere to keep a boat.