This paper evaluates 4G and 5G mobile network performance in the Finnish-Swedish archipelago for autonomous and remotely controlled vessel operations. Through RF measurements along the Naantali-Långnäs-Kapellskär route, we analyze network coverage across different frequency bands. Results show that sub- 1 GHz bands provide reliable coverage with Reference Signal Received Power (RSRP) values consistently above -90 dBm in the archipelagoes, while higher frequencies offer enhanced capacity near shorelines. In addition to signal strength, we estimate the theoretical capacity of the networks based on RSRP values to better understand their suitability for high-bandwidth maritime applications. The findings demonstrate initial feasibility of using mobile networks for maritime autonomous and remote operations in archipelagic waters, while identifying challenges such as uplink capacity limitations that may hinder the transmission of highresolution video and sensor data. Furthermore, network congestion during peak usage periods may reduce available bandwidth, especially when multiple vessels operate simultaneously. Hybrid connectivity solutions, such as multi-SIM modems, intelligent network selection, and satellite integration, may be needed to address coverage gaps and ensure reliable communication for safety-critical functions.