The currency is the Tanzanian shilling (TZS). Most safari companies and tourist-class hotels quote prices in US dollars, and many will expect to be paid in hard currency.
Cash
Carry some US dollars in clean, undamaged notes, and some shillings for small purchases at markets, restaurants and shops. Small notes are useful, because change for large bills is often hard to find. Change money only at banks or official bureaux de change.
Cards and ATMs
Cards are accepted at many lodges, upper-range hotels and tourist shops, and ATMs are available in Arusha, Dar es Salaam, Moshi and Zanzibar. Outside the main towns and the lodges, cards are of limited use, so keep cash as your primary payment and your card as a fallback.
Exchange rates
Rates move, so we do not quote one here. Check the rate on the day you travel.