More than 500,000 people have signed up to receive communications from the RNLI since it moved to an opt-in-only method with supporters.
The life-saving charity said that since becoming the first charity to make this move, it had seen "positive impacts", with improved response rates to fundraising campaigns and better donor revenue generation.
The RNLI pledged that from 1 January 2017 it would stop contacting people by telephone, email or post unless they had actively given their consent for the charity to do so. When it made the announcement in 2015, the charity anticipated that 225,000 people would opt in to receive information, but by October 2016, 375,000 had done so.
Anjie Rook, director of business services and support at the RNLI, said she was delighted to have reached this new milestone and switching to an opt-in style of communications was the right thing to do in order to reinforce relationships with supporters.
"Having the trust of our supporters is absolutely vital to us and we’ll do everything we can to protect and maintain that trust," she said.
"We’ve already seen some incredibly positive impacts of moving to opt-in-only communications. Our summer appeal in 2016 was the first that went out to our newly opted-in supporter database. It far exceeded our expectations, raising £545,000 with a response rate of 32 per cent, compared with a target of raising £200,000 and a response rate of 10 per cent.
Rook called on the Fundraising Regulator to provide more clarity on the use of the "legitimate interest" concept in the new General Data Protection Regulation, which becomes law in May. She said the existing guidelines were open to interpretation.
She said: "From internal awareness-raising activity and staff training to carrying out reviews of all of our systems, applications and processes that involve personal data, we’re doing everything we can to make sure we’re ready for the switch to GDPR.
"However, we feel it is important that the Fundraising Regulator provides more clarity to charities to define what constitutes an acceptable use of legitimate interest. The current wording in the Code of Fundraising Practice is open to interpretation and might not serve to discourage unethical fundraising practices.
"The more clarity and guidance that can be provided, the better prepared charities will be for this major change in regulation. Of course, there are justifiable uses of legitimate interest for charities, but it’s important that there is no confusion about how it should be used. It’s vital that charities take an ethical approach to fundraising and look after supporters’ data in a responsible way. This is what we’re striving for at the RNLI."