When was the last time you sent a letter? Chances are, it has been a while.

Emails, DMs and text messages have mostly replaced the old-fashioned post.

In Denmark, posting a letter in one of its iconic red mailboxes is no longer an option as the country fully embraces the digital age.

The Danish postal service has ended its national letter delivery service after 401 years.

It is the first country in the world to decide physical letters are no longer essential or economically viable.

"For the past 20 years, we've seen a major decline in letters in Denmark; the majority of all our communication is now electronic," PostNord head of press Isabella Beck Jørgensen told the ABC.

"We are one of the most digitalised countries in the world."

The number of letters being sent in Denmark has dropped by 90 per cent in the past 25 years.

In the year 2000, PostNord delivered nearly 1.5 billion letters. Last year, it delivered 110 million.

Letter deliveries in Denmark have fallen sharply in recent years. (Supplied: PostNord)

With fewer letters being sent, postage stamp costs have soared. Sending a standard letter in Denmark now costs 29.11 krone ($6.84).

PostNord described the decision as "difficult" but essential. About 1,500 jobs will be cut — about a third of its workforce.

Concerns for those still reliant on the letter

The company will now focus solely on its profitable parcel delivery service, which continues to grow each year as online shopping continues to boom.

"The whole world is watching right now, and I think other postal companies and operators really look at the decision we took," Ms Jørgensen said.

"There has actually been a big understanding from the public in Denmark. Most people can't remember when it was the last time they sent a letter themselves."

But it has not been well received by everyone; some advocacy groups warn the shift towards digital is happening too quickly and may leave the elderly and people in remote areas behind.

"There are many who are very dependent on letters being delivered regularly," Marlene Rishoj Cordes, from DaneAge, told Denmark's TV2.

"These include hospital appointments, vaccinations or decisions regarding home care."

Private companies to step in

Since June, PostNord has been removing all 1,500 of its iconic red mailboxes scattered across the country.

It only took three hours for the first 1,000 of the postboxes to be sold for charity — at roughly $472 each. Others will go to museums.

"The interest was enormous, hundreds of thousands of people tried to buy a post box when they were put on sale. We are putting 200 more up for auction next year," Ms Jørgensen said.

PostNord will continue delivering letters to neighbouring Sweden, where the population is less digitalised.

Danes can still send a love letter or a Christmas card in 2026, but only through a private company.

They must either drop it at a shop, or pay extra to have it collected from home, which is available online or via an app.

By law, Danes must always be able to send a letter. If a private company stops delivering them, the government must step in with a new provider.