About the Annapurna Base Camp Trek
There are 2 popular options for the ABC Trek, both out of Pokhara by bus or jeep to the starting point and back from the ending point:
The classic trek starting from Nayapul (or take a bus or jeep to Ghandruk) or an alternate starting point of Kande, ending back in Jinu which typically takes 6-8 days.
We did it comfortably in 7 days. We live about 2m above sea level and are in decent shape. I've seen packages from various agencies that are anywhere from 5-9 days for this route. I really don't recommend attempting it in 5-6 days unless you are in really good shape and coming off another trek or live at a high altitude. Trekking is not a race, it's an endurance event. Take your time and know your limits. Believe me, AMS is the real deal.
ABC trek via Poon Hill which starts in Uleri and also ends in Jinu. It typically takes 9-12 days.
I consider Poon Hill a warmup for ABC. The good thing about this option is if you're not sure you are up for the full trek there are some easy outs from both the 3rd and 4th day. don't be fooled by the elevation charts out there, after Chhomrong it is up and down in excess of 700m to cross rivers. it's not all uphill or downhill either direction until Deurali, then it's a steady uphill to ABC. Poon Hill by itself is a good introductory trek if you are new to this type of adventure.
You can also combine ABC with the Annapurna Circuit Trek if you have the time.
Permits: You will need a Trekkers’ Information Management System (TIMS) card, which right now is NPR 2,000 (about $17USD), and an Annapurna Conservation Area Permit (ACAP), which is NPR 3,000. If you are trekking with an agency, they will take care of the permits for you.
Both permits can be obtained in Kathmandu from the Nepal Tourism Board on Exhibition Road, about a 25 minute walk from Thamel.
They can also be obtained in Pokhara at the Tourist Police Office and Permit Office which is on Damside Road near the Nepal Immigration Office.
What's needed to get a permit: Your passport and 2 passport photos along with the permit application.