Visa regulations
Citizens of the following countries/territories can enter Nicaragua without a visa: Andorra, Anguilla, Antigua and Barbuda, Australia, Austria, Bahamas, Bahrain, Barbados, Belgium, Belize, Brazil, Brunei, Bulgaria, Costa Rica, Croatia, Cyprus, Denmark, Estonia, Falkland Islands, Finland, France, Germany, Gibraltar, Greece, Holy See, Hong Kong, Hungary, Iceland, Ireland, Israel, Italy, Japan, Kuwait, Latvia, Lithuania, Liechtenstein, Luxembourg, Macao, Macedonia, Madagascar, Malaysia, Malta, Marshall Islands, Mexico, Monaco, Netherlands, New Zealand, Norway, Paraguay, Panama, Poland, Portugal, Qatar, Saint Kitts and Nevis, St. Lucia, Saint Vincent and the Grenadines, San Marino, Singapore, Slovakia, Solomon Islands, South Africa, South Korea, Spain, St. Helena, Swaziland, Sweden, Slovenia, Switzerland, Taiwan, Turkey, Trinidad and Tobago, Tuvalu, United Kingdom, United States, Vanuatu, the Vatican City (Holy See) and Venezuela.
Other tourists can obtain a Tourist Card for US$10 valid for 1 month to 3 months (depending on citizenship - Canada and USA are allowed 90 days) upon arrival, provided with a valid passport with at least six months to run. There is also a US$32 departure tax which is included in airfares with major airlines (American, Continental, COPA and TACA definitely). The tourist card is valid in the other CA-4 countries, El Salvador, Guatemala, and Honduras, although it sometimes requires a discussion with immigration officials that this accord is in effect, since they are quite compelled to sell more tourist cards.

By plane
You will fly into the international airport in Managua. Flights from the U.S. arrive from Houston, Miami, or Atlanta. Spirit Airlines opened in August 2007. Managua is also serviced by American Airlines, Continental, Taca, Aeromexico and Delta.
In July, 2010, Nicaragua changed its fee to enter the country from US$5 to US$10. Try to have exact change.
Tourist visas are not issued, instead tourist cards or provided and are valid for three months for US citizens as well as for people from the EU and Canada. There will be taxis right outside, these are relatively expensive (US$15 for the 20 Km trip to Managua centre) , or you can walk out to the road and try to flag down a regular cab. Some taxi drivers may try to overcharge, particularly seeing a foreign face, and may start with US$10, but a price around US$3-6 or 60-100 Cordobas is appropriate from the airport. You can also arrange a shuttle pickup to take you to nearby cities like Granada, a popular option for tourists who do not want to spend a night in Managua. It is recommended to have your hotel or language school arrange a shuttle when possible. There are also private services such as Paxeos.
You can also fly into the tiny Granada airstrip from San Jose.

By car
There are two border crossings to Costa Rica, Penas Blancas west of Lake Nicaragua and Los Chiles east of it. You have to take an US$10 boat to cross at Los Chiles. It is actually not possible to cross into Nicaragua via Los Chiles by car. There are three major border crossings to Honduras. Las Manos is on the shortest route to Tegucigalpa, the others ones are on the Panamerican Highway north of Leon.
Foreigners have to pay US$12 to enter the border.

By bus
International buses are available between Managua and San Jose, Costa Rica (also stopping briefly in Rivas and Granada), San Salvador, El Salvador (stopping briefly in Leon) and Honduras. Some buses will continue to Panama City or Guatemala City. The buses are relatively modern with air conditioning, and make stops for fuel and food along the way. However, if you plan on taking this form of transportation, you should plan ahead. Buses between the major cities can fill up days ahead of departure dates. See following companies: Transnica, Tica Bus and King Quality. Another option is to be picked up in the smaller cities along the route, ask for the local ticket office. There are also cheap (but terribly uncomfortable) "Chicken buses" a few times a week between managua and guatemala city (US$20), that stop in major cities like Leon.
An alternative way to travel across the border is take a bus to/from a major city that drops you off at the border. You can then cross the border and board another bus. This is a common strategy for travelers, especially on the Costa Rican/Nicaraguan border. This method takes longer, but is much cheaper and can be done on a moment's notice.

By train
There are no passenger rail lines between Nicaragua and its neighbors.