Diaselo, Kastanorema, Agio and Dimitrios

This easy coastal-and-ravine walk on Alonissos links the upland pass at Diaselo with Kastanorema and the beach at Agios Dimitrios, covering about 8 km / 5 miles with roughly 100 m / 330 ft of elevation gain. The route is generally gentle, but the terrain is more varied than the numbers suggest: expect a mix of dirt road, stony footpath, sections beside the old reservoir, and uneven ground in and around the ravine itself. The trail is waymarked with red marks and has signposting at the start, though it is still worth loading the route in HiiKER before setting out. (topoguide.gr)

The walk begins near the mountain pass known locally as Diaselo on the Patitiri–Gerakas road, on Alonissos in the Northern Sporades. A useful landmark for the start is the signed turnoff to Kastanorema on the main road, about 4.6 km before Gerakas; from there, a dirt and gravel road descends for around 1.2 km toward the old Kastanorema dam and reservoir, where the path continues. (exploring-greece.gr)

For hikers arriving by car, the simplest approach is to drive from Patitiri or Alonissos Town along the road toward Gerakas and look for the signed Kastanorema turn near the pass. Road access is straightforward by island standards, but the final approach is on dirt and gravel, so drive slowly. If using public transport, first reach Alonissos by ferry via Patitiri, the island’s main port, with ferry links from Volos, Agios Konstantinos, Kymi/Mantoudi in Evia, and nearby Sporades islands depending on the season. On the island, municipal buses operate on Alonissos, with current services and ticketing managed through the municipality; because island timetables are seasonal, it is wise to confirm the latest bus schedule before relying on it for a point-to-point hike. (alonissos.gr)

What the route feels like

From Diaselo, the route drops gradually toward the reservoir, so the opening section feels open and exposed compared with the greener middle part of the walk. The old waterworks are one of the defining features here. Kastanorema is the largest ravine on Alonissos, extending for more than 7 km in simplified course, and its midsection narrows into a small gorge-like passage. Although the walls can be steep, the bed itself is described as passable, with only a few step-like obstacles. That makes this a good choice for walkers who want a little variety without committing to a strenuous mountain route. (topoguide.gr)

As you move beyond the dam, the landscape shifts from road walking into a more natural drainage corridor. After rain, this is the part to treat with the most caution. Kastanorema does not have permanent flow, but runoff can continue for several days after heavy weather, and wet rock or loose gravel can make footing less secure than the “easy” rating suggests. In dry conditions, the route is much more straightforward. Good grip matters more here than fitness. (topoguide.gr)

The lower part of the route eventually reaches the coast near Strovili Beach before continuing toward Agios Dimitrios. If you are walking the full line from Diaselo to Agios Dimitrios, the finish is especially scenic, with the contrast of pale shore, clear water, and the rugged folds of the island behind you. Agios Dimitrios itself is one of Alonissos’s best-known beaches, and the coastal setting gives the walk a satisfying change of character after the inland ravine. (topoguide.gr)

Nature and wildlife

This is one of the more interesting short walks on Alonissos for plant life and birdwatching. Vegetation along Kastanorema includes kermes oak, evergreen oak, and Cretan maple, with arbutus and heather also present in parts of the drainage. In places, the route passes through Mediterranean maquis, while more open patches reflect older agricultural use and long-term grazing pressure. (topoguide.gr)

The reservoir adds another layer of ecological interest. Although artificial and no longer operational as part of the island’s water-supply system, it has become