It is possible to get a buy to let mortgage with a deposit of just 15%; however, there are very few products available in this bracket and the rate you will pay will be high. If you are new to buy to let, you may not even qualify for these high loan to value products.
Rates and incentives begin to get much more competitive with a deposit of 25% or more if you can afford it.
A specialist buy to let broker will be able to advise you on the most suitable mortgage for your circumstances. You can send us an email, or call us on 0845 345 6788 to find out what options are available to you.