The Annapurna Circuit is a famous multiday loop around the Annapurna Massif offering stunning views of its peaks up to 8,000m. This route is more than just spectacular scenery since it passes through four zones of distinct cultural heritage (Lamjung, Manang, Mustang and Myagdi).
While the Annapurna Circuit is technically a 180 mile loop, most trekkers do the 128 miles counterclockwise horseshoe from Besisahar (800m) in the east, up north over Thorung La Pass (5,400m), and down southwest to Naya Plu (1,050m). This 128 mile section, which is shared with donkeys, goats and water buffaloes, typically takes about 17 days. Although the journey passes through remote wilderness gorges and high alpine passes with breathtaking vistas, you should not expect a solitary journey since about 60,000 trekkers pass this way annually. It is more of a roaming international village following you along the way.
Sadly, this famous dirt road route is currently being paved. As of early 2010, the western half has been paved from the western base of Thorung Pass at Muktinath all the way down south to Naya Pul. The eastern half is scheduled to be paved to Chame by 2011 and to Manang by 2012. With the paving of each section, the typical trip time decreases as more trekkers opt for 4WD jeeps instead of hiking in dust and exhaust. Matter of fact, by October 2010, it was rare to find any trekkers on the west side south of Kagbeni due to endless exhaust spewing vehicles. Before setting out, check the status of road construction since it may close sections of the route as it did in late 2009.
The good news is that there are several side trek extensions gaining popularity. The most popular is the extension from Naya Pul heading northeast up to the Annapurna Base Camp (aka Annapurna Sanctuary Trek) at 4,095m, which takes 10 days. Another side route is from Manang heading west through Khangasar up to Lake Tilicho at 4,920m (a 3 day hike from Manang). From Lake Tilicho, you could continue west over Meso Kanto pass (16,800 feet) and down to Jomsom.
Most trekkers arrive into Nepal via Kathmandu and stay a night or two in the Thamel neighborhood which is know for its trekking supplies. A cheap trekking permit and TIMS card (about 2,200 NPR) are required upon arrival into Kathmandu from the Annapurna Conservation Area Project Office on Tridevi Marg. There are several permit checkpoints along the Annapurna Circuit. And, there is a chance you may have to pay additional unofficial permit fees (aka donation) to the Maoist Rebels along the way. By the way, bring adequate cash (at least 1,000NPR/day) for the entire trip since ATMs are rare and travelers checks may not be widely accepted. This is not an inexpensive trek as many seems to falsely believe. It is not uncommon for trekkers to run out of money.
To reach the starting point in Besisahar, you will want to fly into Kathmandu Tribhuvan airport. Stay at least one night and pick up your permit. Its best to stay somewhere that has an airport shuttle. To get to Besisahar from Kathmandu, there is a regular bus from the Gonga Bus park. To return from Naja Pul, take a bus or taxi to Pokhara. Then, take a bus back to Kathmandu (check with Greeline Tours).
A great way to keep a free form journey is to stay in teahouses, which do not require reservations -- just make sure you are entering before 3pm to ensure the best selection of rooms (and take a shower right away to ensure hot water!). Along the Annapurna Circuit, there are villages with guesthouses every couple hours. The rates of all these guesthouses in each village are usually the same. Typically, you will need a three season sleeping bag since linens are not provided.
Make sure not to underestimate the climb over Thorung La Pass (5,416m / 17,769 feet) where the temperature is usually below freezing. Prepare for trekking through deep snow and encountering snowstorms. Plan on several days for the approach from Manang for acclimatization. For the final push over the pass, start in early predawn to get down to Muktinath before the afternoon headwinds howl up the valley (budget a mere 0.5 miles per hour -- no kidding!). This pass is why most trekkers do the route counterclockwise. The ascent west to east over the pass is just too rapid for most unacclimated trekkers.
Tip: A good resource is the Annapurna Trekking Map And Complete Guide by Partha Banerjee, which seems to only be found in Kathmandu. Also, plan to purify all water throughout the entire trek (tap water is not potable for foreigners). Consider bringing antibiotics and diamox.
October and November are suppose to be the driest months and most popular for trekking. While April and May can be beautiful with blooming rhododendron forests, the rain is more frequent and the leeches can be a nuisance.
Most travel agents and hotels will tell you that a guide and porters are required, but this is not true. If you do choose to use a guide and/or porter, make sure to contract with them directly to insure they get the money.
Overall, Annapurna Circuit is the 1st most popular walking & backpacking of all 3 hiking in Nepal.