Press officer Matthew Robinson-Royle said the charity had been investigating the feasibility of the service since 2002, and was now ready to release it across the UK and Ireland.
'We've done a photoshoot with Danny McNamara from [rock band] Embrace to generate interest with the dailies and music press, and we're doing a lot of work with youth titles, too,' he said. Youth-oriented websites have also been targeted, he added.
The Samaritans introduced an email service in 1994, and sees the text service as the next step in timely emotional support.
The rollout follows a trial involving 100,000 people in December.
The charity claims all messages will be replied to within ten minutes.