The article presents crystal structure, composition, optical, electrical and thermoelectric properties of semi-transparent CuI films produced in different modes of the cost-effective and large scalable method Successive Ionic Layer Adsorption and Reaction (SILAR) on flexible poly(ethylene terephthalate) (PET) substrates. The obtained data together with the analysis of output thermoelectric characteristics of p-type thermolegs based on these CuI films are used to select the SILAR mode to create semi-transparent p-type thermolegs for a new flexible wearable thin film thermoelectric generator (TEG). The best obtained flexible p-CuI thin film single thermoleg demonstrates output power 17.1 mu W/m(2) at the temperature gradient Delta T = 35 K at near-room temperatures. Therefore, CuI films produced in such mode of the SILAR method on the flexible PET substrates can be used as a part of a new lightweight low cost flexible wearable thin film TEG for a production of electrical energy for low-power devices due to absorption of low-potential heat.