There is no direct connection from Durban to Underberg. However, you can take the car train to Pietermaritzburg then take the taxi to Underberg. Alternatively, you can drive from Durban to Underberg in around 2 h 43 min.
How to get from Durban to Underberg
From Durban car train to Pietermaritzburg then taxi to Underberg. 4 h 55 min R 1 997. From Durban drive to Underberg. 2 h 43 min R 299. From Durban shuttle to Underberg. 3 h 3 min R 449. From Durban bus to Pietermaritzburg, taxi to Pietermaritzburg, then shuttle to Underberg. 3 h 53 min R 637.