He was born in the (then) British city of Dublin, Ireland, from a partially Basque noble family of the French province of Soule. His father, Michel Abbadie, was born in Arrast-Larrebieu and his mother was Irish. His grandfather Jean-Pierre was an abbot and a notary in Soule. The family moved to France in 1818 where the brothers received a careful scientific education. In 1827, Antoine received a bachelier (bachelor) degree in Toulouse. Starting in 1829, he began his education in Paris, where he studied law.
He married Virginie Vincent de Saint-Bonnet on 21 February 1859, and settled in Hendaye where he purchased 250ha to build a castle, and became the mayor of the city from 1871 to 1875.
Abbadie was a knight of the Legion of Honour, which he received on 27 September 1850, and a member of the French Academy of Sciences. He died in 1897, and bequeathed the Abbadi domain and castle in Hendaye, yielding 40,000 francs a year, to the Academy of Sciences.
In 1835 the French Academy sent Antoine on a scientific mission to Brazil, the results being published at a later date (1873) under the title of Observations relatives à la physique du globe faites au Brésil et en Éthiopie. In 1837, the two brothers started for Ethiopia, landing at Massawa in February 1838. They journeyed throughout Ethiopia, travelling as far south as the Kingdom of Kaffa, sometimes together and sometimes separately. In addition to his studies in the sciences, he delved into the political fray exerting influence in favor of France and the Roman Catholic missionaries. While in Ethiopia they returned to France in 1848 with notes on the geography, geology, archaeology, and natural history of the region.
Antoine became involved in various controversies relating both to his geographical results and his political intrigues. He was especially attacked by Charles Tilstone Beke, who impugned his veracity, especially with reference to the journey to Kana. But time and the investigations of subsequent explorers have shown that Abbadie was quite trustworthy as to his facts, though wrong in his contention—hotly contested by Beke—that the Blue Nile was the main stream. The topographical results of his explorations were published in Paris between 1860 and 1873 in Géodésie d'Éthiopie, full of the most valuable information and illustrated by ten maps. Of the Géographie de l'Éthiopie (Paris, 1890) only one volume was published. In Un Catalogue raisonné de manuscrits éthiopiens (Paris, 1859) is a description of 234 Ethiopian manuscripts collected by Antoine. He also compiled various vocabularies, including a Dictionnaire de la langue amariñña (Paris, 1881), and prepared an edition of the Shepherd of Hermas, with the Latin version, in 1860. He published numerous papers dealing with the geography of Ethiopia, Ethiopian coins and ancient inscriptions. Under the title of Reconnaissances magnétiques he published in 1890 an account of the magnetic observations made by him in the course of several journeys to the Red Sea and the Levant. The general account of the travels of the two brothers was published by Arnaud in 1868 under the title of Douze ans dans la Haute Ethiopie.
Antoine was responsible for streamlining techniques towards geodesy, along with inventing a new theodolite for measuring angles.
Basque through his father, Abbadie developed a particular interest about the Basque Language after meeting the Prince Louis Lucien Bonaparte in London. He started his academic work on Basque in 1852.
A speaker of both Souletin and Lapurdian, a resident of Lapurdi, Abbadie considered himself a Basque from Soule. The popularity of the motto Zazpiak Bat is attributed to Abbadie, coined in the framework of the Lore Jokoak Basque festivals, fostered by himself.
Abbadie gave his castle home the name Abbadia, which is the name still used in Basque. However, in French it is usually referred to as Chateau d'Abbadie or Domaine d'Abbadia, and locally it is not unusual for it to be called le Chateau d'Antoine d'Abbadie.
The château was built between 1864 and 1879 on a cliff by the Atlantic Ocean, and was designed by Viollet Le Duc in the Neo Gothic style, and is considered one of the most important examples of French Gothic Revival Architecture. It is divided in three parts : the observatory and library, the chapel, and the living quarters.
Nowadays the château still belongs to the Academy of Science to which it was bequeathed in 1895 on condition of its producing a catalogue of half-a-million stars within fifty years' time, with the work to be carried out by members of religious orders.
The château was classified as a protected historical monument by France in 1984. Most of the château property now belongs to the Coastal Protection Agency, and is managed by the city of Hendaye.
Antoine received the French Legion of Honor on 27 September 1850 with the order of chevalier or knight. He was a member of the Bureau des Longitudes and also the French Academy of Sciences. Both brothers received the grand medal of the Paris Geographical Society in 1850.