Who needs an ad-blocking app when your telecom operator will prevent ads from reaching your mobile device?

Wireless operator Digicel will soon begin blocking online advertising from traveling across its networks in the Caribbean and South Pacific, the company announced Wednesday.

German telecommunications group Deutsche Telekom is also considering blocking advertising on its networks, a person familiar with the matter said.

Jamaica-based Digicel said online advertising companies such as Google, Facebook and Yahoo will now be required to pay to deliver ads to its subscribers, or can expect to have them blocked.

“Companies like Google, Yahoo and Facebook talk a great game and take a lot of credit when it comes to pushing the idea of broadband for all – but they put no money in. Instead they unashamedly trade off the efforts and investments of network operators like Digicel to make money for themselves,” said Denis O’Brien, chairman of Digicel Group, in a statement.

Digicel has 13.6m subscribers across the Caribbean, Central America and the South Pacific.

Google declined to comment on Digicel’s move. Facebook and Yahoo did not immediately respond to requests for comment.

In the coming months Digicel said it plans to begin blocking all in-app and mobile Web advertising across its networks in 31 markets, except the ads that appear on a handful of popular local news properties. The company is considering giving users an opportunity to opt out of ad blocking if they wish, but it will be enabled by default.

To power the blocking, Digicel has partnered with an Israel-based startup called Shine Technologies, which specializes in network-level ad-blocking technology. Shine is currently in talks with a number of carriers globally, according to people familiar with the company, including Deutsche Telekom, which has a controlling stake in T-Mobile US Inc.

Deutsche Telekom did not respond to requests for comment.

It isn’t clear whether U.S. carriers are considering blocking ads in their networks. Verizon Communications Inc., AT&T Inc. and Sprint Corp. did not immediately respond to requests for comment.

For now, U.S. consumers are blocking ads by installing software on their computers or mobile devices. The practice is growing, threatening the business model of many ad-supported online sites and services. Mobile-device giant Apple brought additional attention to ad-blocking by including tools to help power it in the latest version of its ios operating system, released in mid-September.

Digicel said the removal of ads across its networks will help ensure a better experience for its customers, in addition to encouraging online ad companies to share revenue with it. Ads, like all content, require bandwidth to load and currently account for as much as 10% of Digicel’s customers’ data plan allowance, the company said.

Write to Jack Marshall at Jack.Marshall@wsj.com

Corrections & Amplifications:

Deutsche Telekom has a controlling stake in T-Mobile US. An earlier version of this article incorrectly stated that Deutsche Telekom operates the U.S. carrier.