Unicode, the authority on computer text and characters, has already approved adding the three flags to the next release of emojis in June.
Technology companies such as Apple, Google, Microsoft and Facebook will be able to introduce the flags to their software from July.
A UK flag is already available on smartphones and other devices.
Unicode develops the mechanism for making the flags available, but manufacturers have to add the new emojis to their keyboards.
Emoji flags already available include those for Ascension Island, St Barthelemy, Curacao, Diego Garcia and Djibouti.
The campaign for a new range of emoji flags was started by Jeremy Burge of Emojipedia and BBC Wales' social media lead Owen Williams in March 2016.

Aberdeenshire-based Harbro Group saw pre-tax profit increase by £800,000, to £3.5m, in the year to the end of June 2016.
This was despite turnover falling by £1m to just over £100m.
Harbro said international sales grew over the year, both in Europe and in new markets further afield.
The Turriff-based company manufactures and supplies feeds for the beef, sheep, dairy, pig and poultry sectors.
It also has a network of 19 shops across Scotland, operating under the Country Store brand. The stores cater for farming and rural communities with a range of products, including fireside supplies, country clothing and footwear.
In accounts filed with Companies House, the company said: "As always, the outlook for agriculture is difficult to predict.
"We have certainly been experiencing challenging times over the last 12-18 months but the industry is a robust one.
"The impact of Brexit is still to be fully understood, although the board are confident that the group will be well positioned for whatever business challenges this may bring about."

The money was raised by angel syndicate Equity Gap, along with venture capital firm Par Equity, US syndicate Aero-Den and the Scottish Investment Bank.
The move has led to five new skilled jobs which have been filled by former oil and gas supply chain workers.
The company said it planned to add further posts in the future.
Vert Rotors was founded by Olly Dmitriev in 2013 and produces ultra compact low-vibration gas compressors for aerospace, medical and other applications.
The funding will be used to increase capacity at Vert's manufacturing facility in Gracemount and expand its customer base.
Mr Dmitriev said: "This investment brings valuable highly skilled manufacturing jobs to Edinburgh and allows Vert Rotors to increase our sales outreach.
"Our products are fully manufactured in Scotland and exported to Europe and the USA. We look forward to scaling up our operations following this investment."
Jock Millican, from Equity Gap, said: "Vert Rotors has potential to disrupt the established marketplace significantly with its high quality products.
"Olly has an excellent track record in business and has a clear vision for the future of the company."
Emoji flags for Wales, Scotland and England could be available on tablets and smartphones by the summer.
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One of Scotland's largest animal feed producers has posted a rise in profits, despite reporting a "challenging" year for the industry.
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Gas compressor maker Vert Rotors has been given a £1.5m funding boost to scale up manufacturing at its factory in Edinburgh.