Photodriven seawater splitting is considered to be one of the most promising techniques for sustainable hydrogen production. However, the high salinity of seawater would deactivate catalysts and consume the photogenerated carriers. Metal vacancies in metal oxide semiconductors are critical to directed electron transfer and high salinity resistance; they are thus desirable but remain a challenge. We demonstrate a facile controllable calcination approach to synthesize TiO2 nanofibers with rich Ti vacancies with excellent photo/electro performances and long‐time stability in photodriven seawater splitting, including photocatalysis and photo‐electrocatalysis. Experimental measurements and theoretical calculations reveal the formation of titanium vacancies, as well as unidirectional electron trap and superior H+ adsorption ability for efficient charge transfer and resistance to corrosion by seawater. Therefore, atomic‐/nanoscale characteristics and mechanism have been proposed to clarify the generation of titanium vacancies and the corresponding interfacial electron transfer. Erosion of corrosion: TiO2 nanofibers with rich Ti vacancies have been designed by a facile controllable calcination approach. They exhibit efficient charge transfer and resistance to corrosion by seawater owing to a unidirectional electron trap and superior H+ adsorption; which contribute to excellent activity and long‐time stability in photodriven seawater splitting. This study could provide a promising strategy for the design of efficient semiconductors in marine applications.