The R339 is a Regional Route in South Africa that connects Knysna with Uniondale via Avontuur.

It is primarily a gravel road and crosses the Langkloof Mountains at Prince Alfred's Pass.

It meets the north-western terminus of the R340 and heads into the Prince Alfred's Pass.

On the other side, it meets the R62 at Avontuur at a staggered interchange.

[1] The tarred section of the road between Avontuur and Uniondale was closed in 2007 due to flood damage[2] but was since re-opened.