The present invention provides a flexible pipe having excellent blister resistance in a high-temperature and high-pressure environment even though including a thick resin pipe. The flexible pipe includes a resin pipe having a thickness of greater than 5 mm. The resin pipe is formed from a resin having a CO2 permeability coefficient P(CO2) of 20×10−9 cm3·cm/cm2·s·cmHg or lower at 150° C., a CH4 permeability coefficient P(CH4) of 10×10−9 cm3·cm/cm2·s·cmHg or lower at 150° C., a ratio D(CO2)/S(CO2) between a CO2 diffusion coefficient D(CO2) and a CO2 solubility coefficient S(CO2) of 3×10−5 Pa·m2/s or higher at 150° C., and a ratio D(CH4)/S(CH4) between a CH4 diffusion coefficient D(CH4) and a CH4 solubility coefficient S(CH4) of higher than 15×10−5 Pa·m2/s at 150° C.