These islands are visited for their beaches, their pine forests and their nature in general, as well as for some of their appealing and traditional architecture.
Skiathos, closest to the mainland, is the most touristic, famed for its numerous sandy beaches, though not all are lovely or accessible, and the best ones get much too crowded in season. Skiathos also has some good walking trails, a nice old town in its port (and a commercial new town), quite a few monasteries and churches, an islet, and some caves.
Skopelos, the next island out from the mainland, is less touristic, has the nicest harbor town in these islands, traditional crafts, a castle, some good museums, some fine sandy bays (though less beaches than Skiathos) , pine forest, olive and fruit orchards, many churches and monasteries.
Alonissos boasts a large marine park, Europe's first National Marine Park, established in 1992 to protect the rare and endangered Mediterranean monk seal. The island itself is a part of the park, as well as some of its eight islets.
With beautiful water, sand and pebble beaches, pine and oak forests, fruit and nut trees, and great hiking, Alonissos is a haven of ecotourism. On the islets not off bounds to visitors, one can enjoy a fine combination of sandy beaches, caves, woods, monasteries, fishing. The islet of Piperi, one of the northeastermost islets where visitors are banned, is home to 350 to 400 pairs of Eleonora's falcon, along with 30 species of other birds, some of them rare and threatened, as well as rare plant and animal species. Dolphins and monk seals can be seen in the waters here as well.
Skyros, the largest and most remote of the Sporades group, has a beautiful harbor town which resembles those of the Cyclades, fine traditional houses with ornately crafted and decorated interiors, folklore museums, pine forest, farmland, some fine beaches, and traditional pre-Lenten festivities and customs.