Space-air-sea communication networks are of great interest to meet the demand for close and seamless connections between space, land, and ocean environments. Wireless light communication can expand network coverage from land to the sky and even the ocean while offering enhanced anti-interference capabilities. Here, we propose and establish an all-light communication network (ALCN) for space-air-sea integrated interconnection, which merges underwater blue light communication, wireless white light communication, solar-blind deep ultraviolet light communication and laser diode-based space communication. Ethernet switches and the Transmission Control Protocol are used for space-air-sea light interconnection. Experimental results show that the ALCN supports wired and wireless device access simultaneously. Bidirectional data transmission between network nodes is demonstrated, with a maximum packet loss ratio of 5.80% and a transmission delay below 74 ms. The proposed ALCN provides a promising scheme for future space-air-sea interconnections towards multiterminal, multiservice applications.