Land and sea are closely intertwined in coastal areas; however, the governances thereof are in isolation, which may lead to complex conflicts that threaten coastal sustainability. The development of marine economic functions is inseparable from the land. Further, most maritime activities also extend to land, thus exerting impacts on local social and economic development. As such, China considers land and sea as integral entities and promotes land-sea coordination (LSC) through territorial spatial planning. This is one of the pioneering attempts in the world to compulsorily promote the integration of land and sea at the national level. Therefore, this study combs the policy background of LSC development and summarizes that the key challenges of LSC in the context of the new round of land and space planning are the determination of planning scope, the connection of the evaluation system, and the coordination of management. This study analyzes the local experience from the perspective of practice to deal with these challenges and proposes three directions for optimization for further research. In this way, LSC could be a sound framework to integrate land and sea sections for the optimal allocation of resources and eco-environmental protection.