While journeying to St Michael's Mount in 1478, William Worcestre was to note that there were ‘147 havens within the space of 70 miles’ from the Tamar down to Penzance. In Cornwall, the points of access to the sea were many, especially on the south coast with its numerous estuaries. Sundry folk therefore exchanged a rich and varied range of goods and ideas across the county's seas. Tin was by far Cornwall's most valuable export, being shipped both legally and illicitly in large volumes. Also prominent among county cargoes was fish, while goods as varied as hides, foodstuffs, wool and narrow cloths were sent overseas too. Many Cornish seafarers resembled John Scarlet and Stephen Pole of Fowey, who in 1344 loaded their vessel with:

In exchange, Cornish sailors can be found importing wine from Bordeaux, iron from Spain, salt from Brittany and a host of other commodities besides. Although Fowey stood out as the county's pre-eminent port, Looe, Padstow and Saltash also enjoyed significant shipping resources, while a multitude of coves and creeks played host to vessels.

Not simply a source of shipping, the peninsula and its ports also held an integral place in a chain of coastal contacts that at its most expansive linked together the Baltic and the Mediterranean. Long journeys in this period were made of a series of short sails between safe havens, a point made by the Abbot of Tavistock in c. 1300, when he complained that his lands on the Scilly Isles were exposed to ships ‘passing between France, Normandy, Spain, Bayonne, Gascony, Scotland, Ireland, Wales, and Cornwall’. The county's increasingly well-developed port structures, such as the quay at Mousehole ‘for common traffic of ships and boats, both of the king's lieges and of foreigners’, proclaimed Cornwall's contribution to growing networks of seagoing connectivity.