The first sightings of the Marshall Islanders by foreigners were made by the Spanish ships sailing in the 16th century. Since the navigational instruments during this time were very crude the locations of individual atolls and islands were often inaccurate. During this time the islands of Micronesia were generally ignored or avoided by the sailing ships. In the 1700s, several British ships were sailing the Pacific and reported sightings of islands in the area of the Marshall Islands. In 1788 the ships Charlotte captained by Thomas Gilbert and the Scarborough captained by John Marshall sailed from New South Wales, Australia, to Canton, China, for the East India Company. During this trip they sailed together through much of what today is known as the Gilbert (Kiribati) and Marshall Islands. In this voyage the ships most often anchored and had direct contact with the people, whereas most of the voyages in the 1500s had merely sightings of the islands.

Lieutenant Otto von Kotzebue of the Imperial Russian Navy sailed the Rurick on several trips through the Marshall Islands in 1816 and 1817. While at Wotje he made friends with two iroojs (chiefs) and from them learned the locations of several other atolls. The Irooj Langedju drew a map in the sand and named all the atolls in the Ratak Chain from Bikar to Milli, and 12 atolls of the Rālik Chain. Kotzebue copied the sketch and it was reproduced in the official account of the voyage, and later was found to have a remarkable resemblance to a modern map including the names given for the islands. He also sailed again through the Marshalls in 1825-26 on the ship Predpriatie. Many other expeditions visited the Marshalls during the 19th century but few gathered as much information, for Kotzebue was able to make friends with the people and recorded what he learned. He also was supported by a scientific staff which gathered information on the flora and fauna of the islands, and an artist who made many drawings of the people and their lives.

Between the two expeditions of Kotzebue, more extensive contact between foreigners and the Marshall Islanders was occurring. Although Kotzebue had a very favorable reception from the people, many of his contemporaries and those who came later clashed with the people, possibly caused by their lack of restraint, personal arrogance, and cruel demands. As a result, trading was largely unsuccessful until after the middle 1800s when the German companies took control of the Marshalls from several rival iroojs, and developed the production of copra. Few whalers ventured into the Marshalls because of the lack of whales, hostilities with the people, and the numerous dangerous reefs which made navigation most difficult.

The missionaries who came to the Marshalls, including the present various types of missionaries mostly found in Majuro and Ebeye, have made a huge impact on the life and customs of the people. The first mission was Protestant (in cooperation with the American Board of Commissioners for Foreign Missions with headquarters in Boston, which had sent missionaries to Hawaii) and was started on Ebon Atoll in 1857. Many missionaries came to Ebon during this time and used it as a staging base for other atolls to the east and north. By 1909 almost all islands and atolls of the Marshalls had an established Protestant mission station.

In 1891 the first Catholics were baptized in the Marshall Islands. As instructed by Rome in 1898, a mission was begun on Jaluit in 1899. During the early 1900s several Catholic missions spread to other atolls such as Likiep, and Arno. Today there are Catholic churches on Jaluit, Majuro, Likiep, Ebeye, and mission churches on some of the other islands. There are Catholic schools on Majuro, Likiep, and Ebeye.

Since Marshallese contact with various missionaries has been long and intense, almost all the people are Christian with the largest percentage being Protestant. Today even the oldest people no longer believe in the traditional ekjabs and anijs (idols and gods), although many people have grown up with stories about them and will display feelings of deep respect and wonder in the old stories. Most people still believe in jitobs (spirits), both good and bad, and are always taking precautions against the bad ones. The form of Protestantism today is strongly influenced by the dictates of the 19th century when smoking and alcoholic beverages were totally forbidden. Also dancing is believed by most people to be sinful and as a result many of the old Marshallese dances have died out. Only recently has some of the strict teachings of the 1800s started to change.

Some of the more recent Christian denominations to be found in the islands are the Assembly of God, Jehovah Witnesses, 7th Day Adventists, Baptists, Mormons, and many locally developed Christian sects. Also two other independent religions are now established in the islands – Islam and Baha’i. Marshallese are basically very religious people and the several types of missionaries seem to be quite successful in finding converts. Although many aspects of the missionary work have been good, especially in the last part of the 19th century when it helped curb the warring between the various iroojs (chiefs), the missionary work among the different Christian denominations at times appears to be dividing people into different factions and may be causing some dissension where none existed before.