Visitors from most countries can stay in Nicaragua for 30 or 90 days without a visa, as long as they have a passport valid for the next six months, proof of sufficient funds (US$200 or a credit card) and, theoretically, an onward ticket (rarely checked). Most border crossings are relaxed. Citizens of Afghanistan, Albania, Angola, Armenia, Bolivia, Bosnia-Herzegovina, Cameroon, China, Colombia, Croatia, Cuba, Dominican Republic, Ecuador, Egypt, Ghana, Haiti, India, Iran, Jordan, Kenya, Liberia, Libya, Mali, Montenegro, Mozambique, Nepal, Nigeria, North Korea, Pakistan, the Palestinian Territories, Peru, Rumania, Serbia, Sierra Leone, Somalia, Sri Lanka, Sudan, Syria, Ukraine, Vietnam and Yemen must have a visa to enter Nicaragua. The Nicaraguan Foreign Ministry (www.cancilleria.gob.ni) has more specifics.
The immigration office (Direccion de Migración y Extranjeria; 265 0014; 8-11:30am & 1:30-3pm Mon-Fri) in Managua can extend your visa for up to three months, for around US$25 per month. Alternately, you could leave the country for 72 hours, which automatically renews your visa.