One explorer certainly claimed he did, but not everyone believed him

In around 330-320 BC, Pytheas of Massalia set out from the Mediterranean bound for far-off and fabled lands where no known Greek had been before: the northwestern reaches of Europe.

He navigated the Atlantic coast, sailed to Scandinavia, and landed on the British Isles. There, he observed the tin mines of Belerion, or Cornwall, and made estimates of how far away it was from home.

Pytheas wrote an account of his voyage, On the Ocean, which became something of a sensation. It has since been lost, though, so what we know about Pytheas comes from other ancient Greek or Roman scholars, many of whom believed he made it all up – his claims of solidified or frozen seas was deemed too outlandish.

Yet it has been suggested that Pytheas actually made it to the Shetland Islands, Denmark and the Baltic – possibly even Iceland, too.

Source: historyextra