4G was recently installed in Guernsey thus you should be able to have broadband without a landline, but it is worth contacting your chosen provider for advice.
Mobile phones and contracts
Sure, Jersey Telecom and Airtel-Vodafone are the only mobile providers in Guernsey. Just as on the mainland, there are various packages: mobile phone handsets, contracts, SIM only, and pay-as-you-go plans for individuals and businesses including Mobile data plans and devices. Vodafone contracts from the UK are not honoured in Guernsey, so you will have to buy a new plan.
Visitors to Guernsey will find that they are likely to be charged at international rates and as a result we recommend that you contact your supplier before your visit. If you use your mobile device a great deal it is probably worth buying a local SIM.
Guernsey residents are charged to roam beyond the Channel Islands. Contact your supplier to discover the rate at which you will be charged for your destination. Some suppliers can sell you an international SIM before your trip so it’s worth investigating if you plan to use your mobile device as soon as you arrive at your destination.