You can obtain a three months visa on your arrival at Sana’a airport (the capital of Yemen). As soon as you have cleared through customs, change some money into Yemeni Riyal (YR.) at the airport, or when in Sana’a, at the any money exchanger (recommended) or you can exchange money at national bank on Socotra .There are about 190 Riyals to the USD and 230 to ERO. Take cash hard currency with you; USD is acceptable on the island with ERO as an alternative. MasterCard, Visa Card, Cheques are not acceptable.