Starting with this weekend's home game against Sunderland, fans visiting St Mary's on a matchday will see the #SaintsFC hashtag embedded into the Chapel Stand.
The move is designed to increase engagement between Southampton supporters who use Twitter, Facebook, Instagram and Google+, and is the latest in a series of social media initiatives launched by the Club.
Last season, Saints became the first British side to display supporters' Tweets on pitchside LED perimeter boards during matches, beaming our fans' messages in front of not only the sold-out crowds at St Mary's but also to the millions watching on television around the world.
Jordan Sibley, Head of Media at Southampton Football Club, commented: "At Southampton we are always looking at new opportunities to innovate and lead the way in what we do, and this includes our social media strategy.
"We recognise that engaging with our supporters is a key method of keeping them informed and feeling part of the Club, and using Twitter is the fastest, easiest way of communicating with them.
"In becoming the first Club to add our official hashtag to our stadium seating we hope to indicate to the Premier League's global audience exactly how to interact with the Club and all of our supporters."
Southampton currently has more than 135,000 followers on Twitter, as well as almost 60,000 Facebook fans. The Club also has an active supporter base on YouTube, Instagram and Google+.
In January of this year, Saints were the first Premier League team to use Twitter's new short video service, Vine – a platform Saints have actively backed
Only last week, Saints became only the second Premier League club to broadcast live on its YouTube channel, beaming Mauricio Pochettino's pre-West Bromwich Albion press conference around the world as it happened.
Earlier this week, the Club also introduced new signing Dani Osvaldo to supporters live on YouTube, with more than 3,000 people watching the stream at any one time.
Back in April, Saints won praise from industry analysts
for its #SaintsFC100k social media campaign, which saw players thank individual supporters for helping the Club break the 100,000-follower mark on Twitter.
Earlier this summer, Southampton was the only football club named in the Social Brands 100
by social media agency Headstream.
It is hoped that, with our official hashtag now permanently displayed at St Mary's, the Club will be more socially-engaged with its supporters than ever as we enter what promises to be an exciting stage of Southampton's continued development.