The Marshall Islands comprises 29 atolls and 5 isolated islands spread across approximately 750,000 square miles of Pacific Ocean, though total land area reaches only 70 square miles. The two parallel chains run northwest to southeast. Ratak Chain lies to the east, Ralik Chain to the west. Nearly all visitor activity concentrates on Majuro Atoll, where the capital sits, and Bikini Atoll, which requires advance permission and specialized dive operator arrangements. Physical access to outer atolls remains limited by irregular shipping schedules and the absence of commercial infrastructure.
Bikini Atoll received UNESCO World Heritage designation in 2010 as the most significant tangible evidence of the nuclear age. The United States conducted 23 nuclear tests here between 1946 and 1958, including the Castle Bravo test on March 1, 1954, which at 15 megatons remains the largest nuclear device the United States has ever detonated. The atoll remains uninhabited. Background radiation levels on most of the atoll have declined to where short-term visits pose minimal health risk according to International Atomic Energy Agency measurements, though the soil retains cesium-137 concentrations that make permanent resettlement unsafe under current guidelines. Dive operators run week-long liveaboard trips from June through October. The lagoon contains USS Saratoga, a 888-foot aircraft carrier sunk during Operation Crossroads in 1946, along with USS Arkansas, a battleship, and several Japanese vessels. Saratoga rests upright at 180 feet. The bridge sits at 100 feet. Penetration diving requires technical certification. Operators report visibility ranging from 80 to 150 feet. Water temperature holds between 82 and 86 degrees Fahrenheit year-round. Current dive operators charge approximately 6,000 to 7,500 US dollars per person for the week, including transfers from Majuro and all diving. The Marshallese government collects a 300 US dollar diving permit fee. Flights between Majuro and Bikini occur only when liveaboard operators arrange charters. No accommodation exists on the atoll itself.
Majuro Atoll forms a narrow ribbon of 64 islands enclosing a lagoon of 114 square miles. The urban center of Delap-Uliga-Djarrit stretches along a southern reef segment roughly 30 miles long and between 250 and 1,000 feet wide at most points. The runway of Amata Kabua International Airport occupies the eastern end. Laura village sits at the western tip of the connected road, approximately 40 miles from the airport by the single paved road. The road ends there. Beyond Laura, the atoll breaks into uninhabited islets accessible only by boat. The lagoon side remains calm. The ocean side receives consistent wind and swell. Local residents swim and fish from both shores. The reef drop-off on the ocean side begins within 50 feet of the beach at most locations, descending rapidly past 100 feet. No established dive shops operate full-time on Majuro as of 2024. Visiting divers typically arrange informal boat trips through hotel contacts. The lagoon interior reaches depths of 120 feet in places but averages much shallower. Snorkeling occurs anywhere along the lagoon shore with reasonable clarity, though visibility depends heavily on recent weather. Water quality declines near the main urban areas due to sewage and runoff.
Alele Museum and Library sits in Delap-Uliga-Djarrit and holds the national collection of Marshallese historical materials, traditional navigation tools, woven handicrafts, and documents related to the nuclear testing period. The museum occupies a modest single-story building. Holdings include stick charts, which Marshallese navigators constructed from coconut midribs and shells to represent swell patterns around atolls, though these navigation methods have largely disappeared from active use. The museum also displays photographs from the German and Japanese colonial periods and documents related to the forced relocation of Bikini and Enewetak populations. Hours vary and the facility sometimes closes without notice. Admission costs approximately 5 US dollars. English labels exist for most exhibits but are minimal.
Arno Atoll lies 12 miles east of Majuro. The atoll comprises 133 islands enclosing a lagoon. No airstrip exists. The government-operated ferry travels between Majuro and Arno approximately once weekly depending on weather and mechanical status. Transit takes three to five hours depending on conditions. Several small guesthouses operate on Arno, charging roughly 30 to 60 US dollars per night. The atoll supports a population of approximately 1,400 people across several villages. The atoll sees few foreign visitors. Families often welcome arranged visits if approached respectfully through Majuro contacts. The reef systems around Arno remain largely pristine relative to Majuro. No formal dive or snorkel operations exist. Visitors arrange informal boat trips with local fishermen. The eastern islands face open ocean swell. The lagoon side remains sheltered. Bird populations on uninhabited islets include frigate birds, terns, and boobies, though no formal wildlife surveys have been published in recent years.