Sure is dropping the prices of some of its wholesale telecoms services by between 44 and 52%.
The move, which the company says is voluntary, comes after a consultation into the price of Guernsey's business telecoms services by the island's communications regulator, the Guernsey Competition and Regulatory Authority.
The change will affect Sure's wholesale leased line products - which enable other networks without their own on-island cable network to provide landline and broadband services to their customers using Sure's infrastructure.
Michael Byrne, the GCRA's Chief Executive, says businesses in Guernsey should notice a difference:
"These price reductions will have a direct cut-through to the cost of doing business in Guernsey and is an excellent outcome for the sector.
I want to commend Sure for the approach it has taken, and I am sure its customers will appreciate the significant reductions it has committed to and how swiftly it intends to implement them."

However, another of Guernsey's telecoms providers - Airtel-Vodafone - says it is disappointed with the outcome of the GCRA's review.
The company's Head of Technology, Avdhesh Chauhan, says it's 'too little, too late':
"This price review exercise has finally happened after many years and was a great opportunity to address the extortionate price imbalances that exist in the leased line market when compared to other jurisdictions such as Jersey and the UK.
Even after the price reduction, prices in Guernsey are still up to 84% higher than Jersey and up to 760% higher than the UK.
Prices in Jersey are also expected to reduce further following the conclusion of an ongoing regulatory review."
He added that the regulator's decision may actually impact the competition:
"The outcome of this price review exercise does nothing to ease the cost of business connectivity.
The GCRA’s final decision is a huge disabler to competition in the island and is a massive setback to invest in newer technology such as 5G which is contingent on reasonably priced leased line connectivity."
Sure's reduced wholesale charges come into effect from Monday 28 March.

Le Tocq should resign as a Guernsey deputy says Lindsay de Sausmarez
L'Ecume II: Lewis Carr jailed for 20 months for fatal collision at sea
Guernsey's former Chief Minister admits making indecent images of children
Guernsey Deputy and wife arrested and questioned by police
Guernsey Post expect to deliver 750,000 parcels this Christmas
Alderney to get a Royal Visit on 15 December
Two airlines bid to operate Guernsey's essential air links
Guernsey overtakes Jersey as top Channel Island for UK Sea Travel