The CP Urbano Porto service from Aveiro north toward Porto stops at Espinho in approximately 30--35 minutes. The same service continues north to Porto Campanhã, making Espinho a natural halfway point on the journey toward the airport - useful for runners whose flight is not until the evening and who want a few hours by the sea before travelling. Trains run frequently; check current timetables at cp.pt.
The train line from Aveiro north to Porto runs along or close to the Atlantic coast the entire way, passing through a sequence of beach towns that all follow the same basic logic: flat grid, long sandy beach, fish restaurants by the water. Espinho is the largest and most developed of these, with the longest promenade and the most choice of places to eat. But Esmoriz, Cortegaça, Silvalde, and Paramos - all stops on the same line between Aveiro and Espinho - are quieter and less visited, each with their own stretch of Atlantic beach. If a smaller, emptier town appeals more than Espinho's boardwalk, any of these is a valid alternative that adds at most ten minutes to the journey.
Espinho station is underground with lift access to street level, which is specifically convenient on post-marathon legs that have formed a view about staircases.
Late April on this coast: Water temperature in the Atlantic in late April is around 15--16°C - cold for swimming, though not impossible. The beaches are not yet at summer capacity; the promenades belong to local residents and dog walkers rather than holiday visitors. The April swells from the North Atlantic are reliable and the surf is visible from the promenade throughout the day.
Espinho
Espinho is built on a flat grid of streets running perpendicular to the coast, a layout that makes orientation easy and hill avoidance automatic.
The Promenade (Avenida 8 and the beachfront path) runs along the seafront for several kilometres, a wide, flat concrete and paving-stone walkway directly above the beach. The Atlantic is immediately below; in late April the waves arrive without the interruption of beach parasols or summer infrastructure. Walk as much or as little as the legs suggest; the promenade has benches at regular intervals.
The beach itself is wide and sandy, extending north and south. The sand is flat and firm close to the water - saltwater, flat ground, and Atlantic air as therapy for tight legs.
The surf at Espinho is consistent in late April, typically 1--2 metres with the harbour jetty to the north creating a right-hand wave the town is known for locally. Watching it requires no physical effort and a bench.
Where to Eat
Espinho's fishing heritage makes the restaurants along and near the seafront specifically good for what the boats have landed that morning. Grilled sardinhas (sardines, available in late April), bacalhau (salt cod, in every preparation Portuguese cooking has developed for it), and arroz de marisco (seafood rice, a wet, soupy preparation with clams, prawns, and whatever else the kitchen adds) are the dishes to find. Look for a marisqueira (seafood restaurant) with outdoor tables facing the sea rather than the tourist restaurants on the main beach avenue.
Staying Overnight
Espinho is adequate for one night if the beach and the early-evening quiet of an Atlantic town is what the trip needs. The more comfortable overnight base is Porto itself (25 minutes further north), which gives you the Atlantic coast day in Espinho and a night in the city. See the Porto itinerary for the full route.
Practical Note
The Urbano Porto trains running north from Aveiro toward Porto stop at all stations on the coastal line. The full sequence between Aveiro and Espinho passes through Ovar, Esmoriz, Cortegaça, Silvalde, and Paramos. Espinho is the last coastal station before the line turns inland toward Porto Campanhã. If you overshoot Espinho, the next stop is Devesas - already in the Porto urban area.