"It was deep. I thought it was a beer can, so I kept fanning and fanning and fanning, and I came up this, and time just stopped. It was amazing. It was amazing to see that gold down there," said diver Michael DeMar.
The ornate chalice is adorned with etched scrollwork, and experts estimate its value at $1 million or more.
Treasure hunters said the chalice was most likely owned by one of the wealthy passengers aboard the Santa Margarita, which sank in 1622.
The chalice is scheduled to be transferred to an area conservation laboratory to be cleaned.