Removes the phosphate from trehalose 6-phosphate to produce free trehalose. alpha,alpha-trehalose 6-phosphate + H2O = alpha,alpha-trehalose + phosphate Inhibited by EDTA and calcium. Diumycin and moenomycin stimulate activity at concentrations of up to 100 ug/ml, and then inhibit at higher concentrations. Optimum pH is 7.5. Thermostable at 50 degrees Celsius for at least 5 minutes. Glycan biosynthesis; trehalose biosynthesis. Was identified as a high-confidence drug target. Belongs to the trehalose phosphatase family.