Why Mgarr ix-Xini wins
This is the best anchorage in the Maltese islands, and it’s not particularly close. Mgarr ix-Xini is a narrow inlet cut into the south coast of Gozo, with steep rocky sides, deep clear water, and a small restaurant on the rocks that does fresh fish and pasta. Boats anchor in the inlet itself, the swim is straight off the boat into 8 metres of impossibly clear water, and the lunch ashore at the restaurant is one of the best meals in the islands.
Anchoring
Sand and weed bottom in 6 to 12 metres in the inlet. Holding can be patchy because the sand is thin over rock, so set the anchor carefully and check it by swimming down. The inlet is too narrow for swing room, so most boats use a stern line ashore to a fixed point on the rocks. Some boats raft up alongside others.
In fresh southerly winds the inlet becomes uncomfortable. Most summer days are calm. Space is genuinely tight, on a peak summer weekend you may not get in.
Practical notes
The restaurant takes bookings and you should make one. The whole experience, anchorage, swim, lunch, more swimming, slow afternoon, is one of the few genuinely unique boating experiences in this part of the Mediterranean. If you do one anchor stop on a Gozo trip, do this one.