San Juan del Puerto was a Spanish Franciscan mission founded before 1587 on Fort George Island, near the mouth of the St. Johns River in what is now Jacksonville, Florida.

The Saturiwa were one of the chiefdoms of the Mocama, the Timucua-speaking people who lived in the coastal areas of what is now northern Florida and southeastern Georgia.

However, the Saturiwa soon made peace with the Spaniards, and Misión San Juan was founded near their main town on Fort George Island prior to 1587.

[6] After 1650, Guale refugees from the next chiefdom to the north along the (present-day) Georgia coast were settled at the mission.

The Spanish abandoned the mission around 1702, partly in response to raids from Native Americans and allied English colonists from South Carolina during Queen Anne's War.