Corrosion of reinforcement steel is one of the primary factors leading to performance degradation of bridge structures located in coastal marine environment. To preserve adequate performance levels of RC bridges under traffic loads and a severe airborne chloride environment, frequent maintenance activities are required. These activities increase the total life-cycle cost (LCC). As an alternative to conventional reinforcement, stainless steel (SS) reinforcement can be a promising option to avoid corrosion problems and reduce the maintenance cost. It is necessary to identify appropriate geographical locations where the use of SS rebars proves economical since airborne chloride intensity depends on the meteorological condition and distance from coastline. In this paper, a novel probabilistic method for LCC estimation of RC girders under traffic and airborne chloride hazards is established. The critical distances from the coastline for SS rebar application in RC bridges under different coastal environments in 30 cities in Japan are determined based on the proposed method.