Britons can now start the process of switching broadband supplier with one phone call.
The simpler rules replace the previous "confusing" set-up, under which different systems were used for some services and suppliers.
The changed regime may not end up being faster because of a 10-day notification period built in to the process.
And, say critics, the changes might mean more attempts to switch people without their permission.
Drafted by regulator Ofcom, the new rules apply to both broadband and landline services from BT, EE, Sky and TalkTalk, which use the Openreach network.
The new rules came into force on 20 June and mean anyone who wants to change broadband supplier now only has to notify the company they wish to move to. That supplier should then handle every aspect of the change.
Ofcom boss Sharon White said the change would help people "take advantage of very strong competition in the landline and broadband markets".
In its guidance about the changes, Ofcom warned people that they may face early termination charges if they tried to switch before a minimum service period or contract period had expired.
ISPs must keep records of migration requests to help spot cases of so-called "slamming", in which people are moved to new suppliers without their consent. Critics have suggested that the new system could be more open to abuse and mistakes.
Before now, swapping supplier meant people had to first contact their existing supplier, cancel their contract and get a MAC code, which they then gave to their new provider to start the migration process.
Ofcom said this process could be "confusing and time consuming" because suppliers ran different systems to handle migration requests.
The "one-touch" migration system is already used for moves to and from fully unbundled services - for example, when customers migrate from TalkTalk to Sky.
Sebastien Lahtinen, from broadband site ThinkBroadband, said the updated rules removed some confusion from the whole process but might not end up being quicker because they did away with the faster MAC migration options some ISPs offered.
"We don't feel this change is going to substantially increase migrations per se," he told the BBC "although as the new system stops a losing provider from offering a retention deal after they receive a migration request, this may increase migration rates slightly."
Mr Lahtinen said anyone contemplating moving would be wise to ring their existing supplier before starting the migration process to see if they could offer a better deal.
The changes do not apply to migration to or from ISPs offering broadband via cable, fixed wireless, satellite or through fibre to the home.