Tokyo Bay likely faces increasing risks of typhoon-induced flooding as sea level rises and typhoons intensify under climate change. A storm surge barrier (SSB) has been proposed to mitigate this risk, yet little investigated. This study presents initial considerations regarding a potential configuration for a SSB protecting Tokyo. The barrier’s requirements and location are identified through boundary conditions and a criteria analysis, respectively. For dimensioning, typhoon parameters (wind speed, atmospheric pressure, wind direction, and precipitation) are derived through probabilistic analysis. A one-dimensional model evaluates water levels during a typhoon to assess the potential SSB location and dimensions. Finally, key SSB dimensions are derived using rules of thumb. Preliminary results suggest that an effective SSB could be located between Haneda Airport and Disneyland. The concept comprises ungated caisson sections separated by a navigational gate and flow inlets equipped with flap gates, offering both storm surge protection and runoff storage capacity. However, this study represents an initial, system-wide assessment at a relatively coarse level. Despite simplifications, the study finds river-ocean interaction crucial for Tokyo, as the surge could induce river flooding during typhoons.