OI offers a prepaid offer named OI Cartão.
The top ups are as follow:
R$10.00 - it gives you R$20.00 credit a day for use in calls to other Oi mobile, long distance to landlines and Oi mobiles for a month.
R$15.00 - it gives you R$25.00 calling credit a day for use in calls to other Oi mobile, long distance to landlines and Oi mobiles, and SMS messaging to any operator within Brazil, also for a month.
R$20.00 - it gives you R$30.00 calling credit a day to call Oi mobile, long distance landlines and Oi mobiles and Internet access.
The fees are as follows:
Internet - R$0.79 per 100 kb block
Local Calls - R$1.54 per minute
Long distance - available on
National Calls
You must use the 31 code before a long distance call, such as 0 31 21 8888-8888 will place a call to Rio de Janeiro (area code 21) to the mobile number 8888-8888
You can check the balance dialing *805