The sixareen or sixern (Norwegian: Seksring meaning "six-oared") is a traditional fishing boat used around the Shetland Islands. It is a clinker-built boat, evolved as a larger version of the yoal, when the need arose for crews to fish further from shore. The first of the sixareens were, like the yoal, imported from Norway in kit form until the mid 19th century, when increasing import duty made it more cost effective to import the raw materials and build the boats in Shetland.

The sixareen was so named because she was crewed by six men, each man rowing a single oar, unlike the yoal where three men rowed a pair of oars each. The size of a sixareen was about 25–30 feet overall, with a beam of 7–8 feet. The boat carried a square sail which was used when the wind was favourable, but often in light winds or in a head wind the crew could row for many hours to complete their journey. Fishing trips usually were over 3 days, with the boats making 2 trips each week when the weather permitted.

As with the yoal, all the parts of a sixareen have names, which are usually found only in the Shetland dialect, although many of the names are derived from the old Norse language. The names of the parts listed here include the English name and where possible, the Norwegian name.