We had a mattress custom made for ours, a little pricey but that was mostly due to the options we specified. They are called trailer queens and are short so they give some walk around room. All trailers that come with a separate bedroom seem to come with the most uncomfortable mattresses ever produced. It seems that there should be an option to pay an extra $50 dollars to not have a mattress come with the trailer so you would be forced to get one that is comfortable. Ours let you feel every spring. The company that made ours said they regularly replace them in trailers and often toss ones still in the plastic wrap, the customer comes from delivery to the shop and has the mattress replaced.