If you want proof that Edinburgh has a genuine seaside, go to Portobello. It's a coastal suburb about 20-30 minutes by bus from the centre, built around two miles of sand and a long paved promenade looking out over the Firth of Forth, and it has kept a completely different rhythm to the Old Town or even Leith: open-water swimmers at dawn, a Victorian pool and bathhouse on the front, and a High Street of independent cafes, bars, restaurants and shops that feels like a proper small town rather than a Tourli list of names. For the wider city picture, see our things to do in Edinburgh hub.
Portobello was its own place long before it was Edinburgh's. It grew into a genuine Victorian seaside resort, with its own pier, amusement park and open-air pool at various points in its history, and only formally became part of the city under the 1896 Edinburgh Extension Act. That separateness still shows: the beach and promenade are the obvious draw, but Bath Street and the High Street carry the actual neighbourhood life, from a well-loved independent bookshop to a beach-side cafe doing its own baking. If you're weighing up where to stay for a trip that includes a Portobello day, our where to stay in Edinburgh guide covers it as one of the options.
The honest shape of a Portobello day is: walk the beach first, then work the High Street and Bath Street for food, drink and shops, with a swim or a sauna session slotted in if the weather and your plans allow. It rewards slow movement more than a checklist, so treat this less as a fixed route and more as sixteen real, verified spots to build your own version of the day around, roughly grouped from the seafront inland and back again.