Swona and Pentland Firth The Pentland Firth separates Orkney from Caithness in the north of Scotland. The islands of Swona and the Pentland Skerries lie in the Firth, which has very strong tides. In rough weather the seas can be treacherous and even in calm weather the tidal streams must be treated with caution. Pentland Firth Pentland Skerries Pentland Skerries Pentland Skerries Swona - west Swona - west Swona Gloup Swona - west Swona Cairn Swona Cairn Swona Haven Swona sunset