The island at its widest is 4.5 km from northwest to southeast and at its longest is 20 km from southwest to northeast. The island is mostly limestone. It is located east of mainland Greece and Magnesia, northeast of Euboea and northwest of the island of Skyros. Alonissos has one main road which leads to three villages in the western part of the island and several unused roads throughout the island.
The village of Alonissos is located on the southern part of the island. It is locally known as Chora. The main port of the island is located in the southeast and is called Patitiri. There is ferry and hydrofoil service from Patitiri to Volos, Agios Konstantinos, and Thessaloniki on the mainland and to the islands of Skiathos, Skopelos and Skyros. The bay at the southern end of the island is also called Alonissos.
Summers are long and hot, in spring and autumn you will need little more than a cardigan to keep away the cool morning and evening breezes and winters are generally mild. You will find it slightly cooler in the island’s village of Chora, set high on the hill.
Alonissos is accessable via ferry from Volos, Agios Konstantinos, and Skopelos. Patitiri is the third stop both from Skiathos harbour and the mainland and takes about 1½ hours from Skiathos and 4 hours from Aghios Constantinos. There are two alternatives in travel to and from Volos: the regular ferry (which takes vehicles and about 5 hours) and the FastCat (which is passengers only, takes about 3 hours, and costs more). Cruise ships dock at the Patitiri Port.
There is no airport on the island itself, but you can fly to either the nearby island of Skiathos in peak season or to Athens on the mainland. From either of these you will proceed to Alonissos by boat.
Out of season on Alonissos there isn't any public transport and you will find that even though there is a bus stop in Patitiri next to the taxi stand and opposite the Alkyon Hotel, there's no bus. This is because out of season the bus does the school run and is therefore otherwise engaged. Arrive here on Alonissos during the height of the season and you will find a regular bus service running between Patitiri and the Old Town and a limited service running between Patitiri and Steni Vala. Tickets are purchased on the bus with the single fare from Patitiri to the Old Town costing 1 euro and from Patitiri to Steni Vala costing 1 euro 10 cents.
With public transport on the island being available only during the summer months, taking a taxi is the main form of transport for visitors unless you rent a car. The taxi rank is opposite the Alkyon Hotel next to the bus stop. Patitiri harbour to the Old Town takes about 10 minutes by taxi and costs 10 euro. For early morning journeys or at public holidays you may pay twice this amount for the same journey. You can also use the taxis to take you to other island destinations such as Votsi, Steni Vala and Milia beach which are accessible via tarmac roads.
Whether it is worth bring your car to the island is debatable. As of August 2014, the ferry cost is about the same as renting a car on the island for two days (about 160 euros). There are numerous car and scooter rental stores in Patitiri. But in the height of the tourist season there may not be any vehicles available. Taxis are a quite cost-effective alternative for getting to attractions in the vicinity - e.g., 12 euros will get you to a very nice beach about 10 minutes out that has a restaurant/bar and tables and chairs under ancient olive trees right behind the beach. The bus ride to the same beach costs less than 2 euros. Asphalt roads run across the south of the island. Roads in the interior turn out to be little more than dirt paths.
Motorbikes and mopeds are popular alternatives to cars. Mopeds in particular are frequently used by local youths and can go to many places that cars cannot go - for example the twisted narrow streets of Patatiri. An additional advantage is that they are cheap to rent - 10 to 15 Euros a day is the usual price. You can rent them easily from the port of Patatiri.
If you start a day-trip with a moped, make you sure you do so on a full tank, as gas stations are sometimes hard to find. An extra stop at a gas station can save a lot of nerves. When renting a moped, check if the profile of the tires is ok and if the brakes work properly. If it is the last vehicle in store, be suspicious - it could be the one that needs a repair badly. Though helmets are not required on the streets, it might be a good idea to ask your rent-a-bike for one, especially if you intend to drive on streets with more traffic.
Sea caves where seals live. Don't expect to see any seals, though, they're too shy to be seen. One of the things you should do if you have some time in Patitiri is visit the Alonissos museum. This is housed in a bright new stone building to the left of the town beach. To get there, go past the bars and tavernas behind the town beach and up the steps at the end. The door to the museum is up the steps. Exhibits are located on the lower ground, ground and first floor with a coffee shop on the second floor. There is a lift to all floors.
As you can see from the inscription below this a private venture undertaken by Costas and Angela Mavriki. Traditional House Museum of Alonissos
The museum opened during the summer of 2005 and is located at the start of the main thoroughfare of the Upper Old Town. When you walk up the steps from the plateia with the war memorial on your right the building on the right hand side is the new museum. The war memorial is attached to the rear wall of the new museum building. On the side of the museum wall you will see a yellow sign as shown below top. The entrance is up the first set of steps on the right and has a sign above the door shown below bottom. Exhibits are located on the ground floor and first floor and recreate the inside of a traditional Alonissos house. There is no entrance fee and it's definitely worth a visit.
In 2012 Alonissos has received the QualityCoast Gold Award for its efforts to become a sustainable tourism destination. Because of this award Alonissos has been selected for inclusion in the global atlas for sustainable tourism DestiNet. 
All fish dishes are delicious as most restaurants only serve the day’s catch. The bakery on the right of the main street in Patitiri has delicious pastries. One cannot miss the famous lobster spaghetti dish of Kyria Tasia in her tavern at Steni Vala and her sister's Soultana desert in the coffee house next door.
The style is hearty rather than overcomplicated. It’s better away from the tourist “chips with everything” areas in the major resorts. Alonissos tavernas generally offer the best menus. Portions are usually generous. The excellence of the local wine is a real bonus, and at good prices, so a night out tends to be inexpensive and a lot of fun!
All the markets in Alonissos produce plentiful and inexpensive food. There are small supermarkets well stocked with local and imported food. Feeding 2 people for a week would cost you around €100.
Restaurants and Tavernas are not expensive – you should be able to eat and drink for around €8 per head, and enjoy a really good meal.
Local wines and spirits are good value, and beer will cost about €0.50 a bottle, cigarettes €3.80 per packet).
The cuisine is best enjoyed at the invitation of a local to go to his house - don’t turn down an invitation. Grilled fish or meat sprinkled with local herbs cooked slowly on an outside charcoal fire is always delicious, especially when it's washed down with some local village wine. Greek salad is well known, of course, and the souvlakia (meat on a skewer) is always to be found in village tavernas.
If you enjoy seafood, find a local Ouzorea that’s used by the locals and try a meze.
At lunchtime, fried calamari with a bottle of chilled Retsina is wonderful.
Breakfast tends to be light, and of the continental variety. Most tourist tavernas now offer full English breakfasts, omelettes and toasted sandwiches.
The tap water is barely drinkable - it's very brackish; locals don't use it at all in cooking. Make sure you buy bottles of water at one of the many supermarkets to take to your hotel room and on outings. Restaurants may serve glasses of ice water upon request, but usually provide cold bottled water for which you pay. Local drinks include Mythos (beer) and Ouzo.
Alonissos is a generally safe destination.