As of June 10th, 2015 the government of Indonesia will allow US Citizens enter Indonesia visa free for stays of 30 days or less.
The visa exemption can only be applied at 9 immigration checkpoints.
1. Soekarno-Hatta International Airport, Jakarta
2. Ngurah Rai International Airport, Bali
3. Kualanamu International Airport, Medan
4. Juanda International Airport Surabaya
5. Hang Nadim International Airport, Batam
6. Sri Bintan Pura Seaport, Tanjung Pinang
7. Batam Center Seaport, Batam
8. Sekupang seaport, Batam
9. Tanjung Uban Seaport, Tanjung Uban
This is not a Business, Work or Visitation (Social) visa. Therefore it cannot be converted to obtain other immigration permits. The maximum stays permitted for the visa on arrival is 30 days. If you plan to stay longer than 30 days you need to apply for a visa.
Single Entry visas are valid for 3 months, multiple entry visas are valid for 12 months. Your passport must be valid for 12 months from date of entry into Indonesia to be eligible for a multiple entry visa.
If you apply for an actual visa (not the Visa Free on Arrival Option) it will be valid starting from the day it is issued. You must enter Indonesia within 90 days of issuance of the visa. You can stay in country up to 60 days.