Just like the Cape of Good Hope, the discovery of Mossel Bay is an important milestone in early Europeans' search of sail routes to the east. At the turning point of the 16th century, King of Portugal D. Juao II was determined to search
for a sail route from Europe to India. The Portuguese King was driven by his ambition to dominate the oceans and hence sent forth an expedition led by the famous explorer Bartolomeu Dias in 1486. The expedition set sail along the west coast of the African continent in search of a route to India.

After over a year of difficult voyage, the fleet almost capsized due to a storm when it was just about to leave the Atlantic Ocean for the Indian Ocean. Due to the experience, Dias decided to name the cape he discovered in 1488 as "Cape of Storm", which was later renamed to Cape of Good Hope. After making his way around the Cape of Good Hope, two sailboats led by the Portuguese explorer discovered Mossel Bay. Dias decided to anchor at Mossel Bay in order to replenish fresh water. During the process, he discovered a fresh water spring at the area and he named it "Aquada de Sao Bras" (watering place of St Blaize) by Dias because he located the spring on the St. Blaise' festival day (February 3 (new calendar)).
With intertwining roots and thick shade, the Post Office Tree is in fact a milkwood tree, which is a tropical plant that excretes milky sap. The tree earned its name in 1500 when a navy commander Pedro de Alaide left a letter in a shoe under the large tree, on his return journey from the east. In 1501, this letter was found by Joao da Nova, commander of a fleet in East India. From then on, any mail posted in the shoe would get special post office tree frank.
 

Mossel Bay is part of the Garden Route. The bay earned its name due to the its abundance of mussels (bivalve molluscs such as pearl mussels). The Dias Museum Complex features an extensive collection of specimens of fish in surrounding waters along with items salvaged from wrecked merchant ships, such as Chinese porcelains (including a large porcelain jar made in Jingde Township in Jiangxi during Ming  
Dynasty), which were highly valued by early Europeans. In an effort to celebrate the 500th year of Dias' discovery of South Africa, a replica of Dias' caravel was built in 1987, which set sail on the same course along the west coast of Africa that Dias had taken 500 years ago. The ship arrived at Mossel Bay on February 3rd, 1988 and it is now on display at the Maritime Museum of the Dias Museum Complex. Visitors traveling to Mossel Bay are strongly recommended to go to the museum and check out the caravel.