The journey from Jember to Semarang covers about 550 km. You can take a train to Surabaya and then a connecting train to Semarang, or a direct bus. The total travel time is around 10 hours. Semarang is a historic port city with a mix of Javanese, Chinese, and Dutch influences.
Total Distance: Driving 550 km, straight-line 450 km.
You will need to change trains in Surabaya.
May to September for dry weather.