The harbor is a brisk and busy port. The bay has a decent sandy beach. There are a few pretty neoclassical buildings and a lovely church. Along the waterfront you can find boutiques, art galleries and tavernas.
Over the headland, a path leads to the stone constructed estate of the Marouli Family and further along to the sandy cove sheltering Gialiskari beach with a taverna and pine stands. This locality has many holiday villas for rich Athenians.
To the north lies Aghio Nicolaou Bay and the village-resort of Vourkari by the Sea where many yachts and pleasure boats loll in the waters. Voukari has several nice hotels, some with balconies opening on to the sea.
There are also efficiency apartments for let. Try just about any restaurant for fresh seafood! You'll see the yachties eating near their moorings.
The Church of Aghia Irini stands on the promitory and nearby, the excavations of the Minoan-Mycenaean settlement. Its discoveries are on display in the Archeological Museum of Ioulis (Tues-Sun, 8:30-3, Tel: 22079) along with other finds from around the island. (The original Kouros of Kea is in the National Archeology Museum in Athens with a copy on display locally.)
At the northern most tip of the island is the very popular beach resort of Otzias. The bay around Otzias is ringed with blooming almond trees, which are beautiful in sping. You can walk up to the Monastery of Panagia Kastriani about a kilometer to the east. There's a great panoramic view from the monastery. The monastery has a miraculous Icon of the Virgin Mary whose properties were discovered in 1708 by two goatherds who were attracted to a mysterious glowing on the mountain side that led them to the icon.