Multiple symbol noncoherent soft output detectors in accordance with embodiments of the invention are disclosed. In a number of embodiments, the multiple symbol noncoherent soft output detector uses soft metrics based on the Log Likelihood Ratio (LLR) of each symbol to provide information concerning the reliability of each detected symbol. One embodiment of the invention includes a receiver configured to receive and sample a phase modulated input signal, and a multiple symbol noncoherent soft output detector configured to receive the sampled input signal and to generate a soft metric indicative of the reliability of a detected symbol based upon observations over multiple symbols.