Do US citizen need visa in Sri Lanka?

Answer 1

no. A passport and onward/return ticket and proof of sufficient funds are required. A no-cost landing visa, valid for 30 days, will be granted only to tourists at the time of entry into Sri Lanka.
yes. Business travelers are required to have a visa prior to arrival.

Individuals traveling to Sri Lanka for purposes other than tourism (e.g., religious work, volunteering or working) must obtain an entry visa from the nearest Sri Lankan Embassy or Consulate before their arrival in Sri Lanka. Foreigners entering Sri Lanka on a landing/tourist visa cannot convert their visa to a non-tourist one, and risk deportation if they engage in activities other than tourism without the appropriate visa.

Visitors staying more than 30 days for any purpose must obtain a visa extension from the Department of Immigration and Emigration in Colombo and pay the relevant visa fees. Travelers must have yellow fever and cholera immunizations if they are arriving from an infected area. Sri Lankan law requires all foreign guests in private households to register in person at the nearest local police station.

Individuals who stay in private households without registering may be temporarily detained for questioning. This requirement does not apply to individuals staying in hotels or guesthouses.
Specific inquiries should be addressed to the Embassy of the Democratic Socialist Republic of Sri Lanka, 2148 Wyoming Avenue NW, Washington, DC 20008, telephone (202) 483-4025, fax (202) 232-7181, contact by e-mail;; the Sri Lankan Consulate General in Los Angeles at 3250 Wilshire Blvd., Suite 1405, Los Angeles, CA 90010, telephone (213) 387-0210; or the UN Mission in New York City, telephone (212) 986-7040. There are several honorary Sri Lankan consuls general and consuls in the United States. Visit the Embassy of Sri Lanka website for the most current visa information.