The most common building blocks for maritime data connections are VSAT, L-Band (Iridium, Fleetbroadband) and 3G/4G/5G. Those adventurous enough could add some more exotic Point-to-Point radio links and whatnots but the first three are the most common. Depending on your application and sailing area the above can be combined. Some combination examples are:
For Coastal Mostly Within National Cellular Range:
4G and local SIM as primary VSAT with low bandwidth as backup
For International Coastal Mostly Within Cellular Reach:
4G and international SIM as primary VSAT with low bandwidth as backup
For Global Sommercial Shipping:
Primary VSAT with sufficient bandwidth 4G and international SIM when near coast or port for additional services L-Band Iridium Certus for operational Backup and GMDSS
For Technical Vessels requiring high throughput:
The largest VSAT you can install (the larger the antenna the lower the OpEx). A performant global 4G router with external antennas and non-steered SIMS In Port Wireless for Large data offload
For Inland Cruise:
Powerful multiple 4G/5G router with high volume SIMs Optional VSAT Backup.
For Larger Cruise Liners:
Extra large C-Band and Ku-Band VSAT combinations Redundant teleports High throughput (upload and download) 4G/5G international SIMs In port Wireless for additional Guest services and Operations.
and for all the above
+ a (redundant-High Availability) Multi WAN router.