Similar to other European countries, you can pay for your calls in two different ways: prepaid or contract.
Prepaid phones: With prepaid phones, you have maximum flexibility since you pay as you go. As you need more credit you simply recharge your card (recargas) at a local supermarket, at your local kiosk (estanco), at the ATM, or online. The minimum amount of credit that you must add is usually between 5 and 10 euros. Prepaid tariffs can work as a kind of contract and include free minutes, free messages and internet as well. If you recharge your card, you will be able to use the services you signed up for. If you don’t pay, you won’t get your free minutes, messages or internet.
Contract: The other option available is to sign a contract. Besides delaying payment until the end of the month, the benefits of a contract are lower calling rates (quite significantly in some cases) and better deals on new phones.
When evaluating which plan is best for you, be sure to read all the other conditions such as the monthly fees ( cuota mensual), the connection cost ( coste de conexión) and the minimum monthly consumption ( consumo minimo). The typical length of a contract is one year. If you cancel before this, you will usually have to pay a penalty. If you unsure about how long you will be staying in Spain, signing a contract may not be the best option for you.
Contracts are fairly easy to obtain on an individual basis. There are no credit checks or need to provide proof of income. The mobile operators usually only require an identity document like a DNI or a tarjeta de residencia and a recent bank statement. All of the mobile companies require that charges are directly debited ( domiciliado) from your bank account. Many new arrivals start with a prepaid phone and then convert to a contract when they have sorted out the paperwork.