The nearest rail head from Agumbe is Udupi. Agumbe is about 50 kms from Udupi. If you are using public transport there are numerous buses from Bangalore to Udupi and Shimoga. Shimoga is about 100 kms from Agumbe. If you are traveling by your own transport Agumbe is located near the town of Thirthahalli which lies between Shimoga and Agumbe. Agumbe can be reached by taking NH-4 till Tumkur , then NH-206 till Shimoga and then NH-13 to Thirthahalli (total distance of 370 km)
Agumbe is located about 100 kms from Shimoga and 50 kms from Udupi. Although KSRTC runs only one Rajahamsa till Agumbe from Bangalore directly there are numerous buses from Bangalore to Shimoga and Udupi.
The nearest railway station from Agumbe is Udupi which is about 50 kms from Agumbe.
There are only two direct trains from Bangalore to Udupi Ypr Kawr Express and Karwar Express. Although there are far many more buses running between Bangalore and Udupi if you have to use bus its better to take a bus to Shimoga. There are far more frequent buses to Agumbe from Shimoga than Udupi.