Route nationale 5a (RN 5a) is a secondary highway in Madagascar of 406 km, running from Ambilobe to Antalaha. It crosses the regions of Diana and Sava.
The section from Ambilobe to Vohemar was completely unpaved and in very bad condition until 2020 when important road works had been undertaken. This part of the route had been paved in September 2022. From Vohemar to Antalaha the road is paved and in good condition.
(north to south)