At the time of writing, the ferry service between Bukoba and Mwanza had stopped operating, and restarting it is taking some time. Hopefully the service will begin again in 2018.
Among the options are buses to the following:
Kampala, Uganda (Tsh20,000, six to eight hours) Two departures daily at 6am and 12.30pm. Visas can be issued at the border.
Kigoma (Tsh28,000, 13 to 14 hours) Every Monday, Wednesday and Friday at 6am.
Mwanza (Tsh20,000, eight hours) Frequent departures between 6am and 12.30pm.