You will need a good warm sleeping bag for the Inca Trail trek. Where possible we recommend you bring your own sleeping bag, however adequate ones can be hired locally (for approximately US$15) but we can take no responsibility for the standard. If you are planning to hire a bag it is a good idea to bring a silk sleeping bag liner to use inside for added warmth and comfort.
A four season* (or -10) bag is recommended for the winter months. At other times you will probably be fine in a 3 season (or -4/-5) bag although this depends on how much you feel the cold and is given as a guideline only. Roll mats are provided on the Inca Trail however for greater comfort and warmth, Thermarest style mattresses can also be hired in Cusco for US$15.
*Please note: If you are travelling in winter and you do not wish to invest in a 4 season bag you may want to consider purchasing a 3 season bag plus a sleeping bag liner and bringing additional clothing