A pioneer is a volunteer Bahá'í who leaves his or her home to journey to another place (often another country) for the purpose of teaching the Bahá'í Faith. The act of so moving is termed pioneering. Bahá'ís refrain from using the term "missionary". The first pioneer to enter a country or region mentioned in `Abdu'l-Bahá's Tablets of the Divine Plan is given the title of Knight of Bahá'u'lláh.
During the Ten Year Crusade which ran from 1953 to 1963, hundreds of pioneers settled in countries and territories throughout the world, which eventually led to the establishment of 44 new National and Regional Spiritual Assemblies and the increase in the Bahá'í population.
The teaching work done by pioneers was done in many different ways including, but not limited to
Shoghi Effendi, the head of the Bahá’í Faith in the first half of the 20th century, has written:
For Bahá'ís, pioneering refers to something similar to missionary work. However, Bahá'ís do not consider pioneering to be proselytism, a word which often implies the use of coercion to convert someone to a different religion.
The following is a letter written on behalf of Shoghi Effendi to an individual:
During Bahá'u'lláh's lifetime (died 1892) he encouraged some of his followers to move to India. When the religion began to grow in India, other Bahá'ís moved on - for example entering Vietnam and other places in 1950s. During the 1950s and 1960s the Bahá'í Faith spread rapidly in Vietnam, and the nearby countries of Indonesia, Malaysia, and the Philippines. From 1957 to 1963 the Bahá'í community in Vietnam had more than tripled.