It was first excavated in 1825 by Jean-Jacques Rifaud, who discovered the two pink granite sphinxes now in the Musée du Louvre, and then by François Auguste Ferdinand Mariette between 1860 and 1864, and subsequently by William Matthew Flinders Petrie from 1883 to 1886.

The Mission française des fouilles de Tanis (MFFT) has been studying the site since 1965 under the direction of Jean Yoyotte and Philippe Brissaud, and François Leclère since 2013.

This accumulation of remnants from different epochs contributed to the confusion of the first archaeologists who saw in Tanis the biblical city of Zoan in which the Hebrews would have suffered pharaonic slavery.

It was not until the discovery of Qantir/Pi-Ramesses and the resumption of excavations under Jean Yoyotte that the place of Tanis was finally restored in the long chronology of the sites of the delta.

[9][a] A temple inscription datable to the reign of Ramesses II mentions a "Field of Tanis", while the city in se is securely attested in two 20th Dynasty documents: the Onomasticon of Amenope and the Story of Wenamun, as the home place of the pharaoh-to-be Smendes.

Although some monuments found at Tanis are datable earlier than the 21st Dynasty, most of these were in fact brought there from nearby cities, mainly from the previous capital of Pi-Ramesses, for reuse.

[15] The 1885 Census of Egypt recorded San el-Hagar as a nahiyah in the district of Arine in Sharqia Governorate; at that time, the population of the city was 1,569 (794 men and 775 women).

[11]: 921  For some time the overwhelming amount of monuments bearing the cartouches of Ramesses II or Merenptah led archaeologists to believe that Tanis and Pi-Ramesses were in fact the same.

They were discovered intact in 1939 and 1940 by Pierre Montet and proved to contain a large catalogue of gold, jewelry, lapis lazuli and other precious stones, as well as the funerary masks of these kings.

[19] In 2011, analysis of high-resolution satellite imagery, led by archaeologist Sarah Parcak of the University of Alabama at Birmingham, found numerous related mud-brick walls, streets, and large residences, amounting to an entire city plan, in an area that appears blank under normal images.

[22] However, the assertion that the technology showed 17 pyramids was denounced as "completely wrong" by the Minister of State for Antiquities at the time, Zahi Hawass.