Wales and France are the two nations that will get us underway - on January the 31st in Saint-Denis - with both sides vying to improve on their 2024 performances.
Ahead of the big kick-off, let's take a look at some key factors for each country.
Ireland
As the reigning champions, the Irish will be aiming to claim the crown once more. If they do so, it'll be their third successful championship on the spin.
Ireland head into the tournament considered by many to be the favourites to win the Six Nations, but do so without head coach Andy Farrell.
Farrell is currently on-task with the British and Irish Lions, so Simon Easterby has stepped up to the plate.
That said, the Irish are undoubtedly the current best team in the northern hemisphere and perhaps it's only France who could give them a run for their money.
In terms of players to keep tabs on throughout the tournament, Sam Prendergast could very well step out of Jack Crowley's shadow to become the star of the Irish team.
Predicted finish: 2nd
Squad
Forwards (21): Ryan Baird, Finlay Bealham, Tadhg Beirne, Jack Boyle, Thomas Clarkson, Jack Conan, Caelan Doris (capt.), Tadhg Furlong, Cian Healy, Iain Henderson, Rob Herring, Cormac Izuchukwu, Rónan Kelleher, Gus McCarthy, Joe McCarthy, Peter O'Mahony, Andrew Porter, Cian Prendergast, James Ryan, Dan Sheehan, Josh van der Flier
Backs (15): Bundee Aki, Caolin Blade, Jack Crowley, Ciaran Frawley, Jamison Gibson-Park, Mack Hansen, Robbie Henshaw, Hugo Keenan, James Lowe, Conor Murray, Calvin Nash, Jimmy O'Brien, Jamie Osborne, Sam Prendergast, Garry Ringrose
England
The English were left wondering what could have been in 2024 as Steve Borthwick attempted to finally get a grasp on his team's identity after taking over as head coach in late 2022.
It felt like a learning experience for England, who now look like an improved outfit. They thrashed Japan 59-14 in the recent Autumn Nations Series and suffered defeat by only narrow margins to rugby juggernauts New Zealand (24-22), Australia (42-37) and South Africa (29-20).
Still, there will need to be improvement if the English are to improve on their last showing at the Six Nations - and their match against old rivals Scotland (for the Calcutta Cup) should be quite telling.
But, the only team to put a dent in Ireland's run during last year's tournament (four wins and one defeat), the English might still feel confident ahead of the 2025 iteration.
Notably, Borthwick has chosen Maro Itoje to replace Saracens teammate Jamie George as captain ahead of the Six Nations.
Predicted finish: 4th
Squad
Backs (16): Oscar Beard, Elliot Daly, Fraser Dingwall, George Ford, Tommy Freeman, Ollie Lawrence, Alex Mitchell, Cadan Murley, Harry Randall, Tom Roebuck, Henry Slade, Ollie Sleightholme, Fin Smith, Marcus Smith, Freddie Steward, Jack van Poortvliet
Forwards (20): Fin Baxter, Ollie Chessum, Alex Coles, Luke Cowan-Dickie, Chandler Cunningham-South, Ben Curry, Tom Curry, Theo Dan, Alex Dombrandt, Ben Earl, Ellis Genge, Jamie George, Joe Heyes, Ted Hill, Maro Itoje (capt.), George Martin, Asher Opoku-Fordjour, Bevan Rodd, Will Stuart, Tom Willis
Wales
Wales stunned with a rash of sub-par performances in 2024. In fact, for those who need reminding, the Welsh lost all five of their matches last year. It earned the 2021 Six Nations champions the Wooden Spoon - only their second ever, and their first since 2003.
Without trying to be too doom and gloom, it would appear the Welsh might struggle again in the 2025 Six Nations.
Under the direction of Warren Gatland, Wales have been able to produce some impressive performances - particularly during his first stint between 2007 and 2019 - but it's been a while since we've seen that.
Since the last Six Nations, Wales have played a total of seven matches and lost all but one - prevailing by the most slender of margins (36-35) over Australia's Queensland Reds.
Wales can take some solace in the fact they were beaten by a slender margin themselves in a match against Fiji (24-19), but it remains to be seen how galvanised Gatland has got his squad.
Predicted finish: 6th
Squad
Forwards (19): Gareth Thomas, Nicky Smith, Kemsley Mathias, Keiron Assiratti, Henry Thomas, WillGriff John, Elliot Dee, Evan Lloyd, Sam Parry, Dafydd Jenkins, Will Rowlands, Freddie Thomas, Christ Tshiunza, Teddy Williams, James Botham, Aaron Wainwright, Taulupe Faletau, Jac Morgan (capt.), Tommy Reffell
Backs (15): Tomos Williams, Ellis Bevan, Rhodri Williams, Ben Thomas, Dan Edwards, Eddie James, Nick Tompkins, Joe Roberts, Owen Watkin, Tom Rogers, Josh Hathaway, Ellis Mee, Blair Murray, Josh Adams, Liam Williams
Scotland
The Scots can be proud of their showing at the 2024 Six Nations, finishing just two points behind England.
It shows Scotland have come some way in recent years, now - it seems - comfortably ahead of sleeping giants Wales and relative minnows Italy.
There is a buzz about the Scottish ranks. They play with a sort of freedom that the likes of England and Wales can't afford, given expectations since the turn of the 21st century haven't been quite as high.
Speaking of England, an argument can now be made - given that Scotland have won their last four head-to-head matches against the English - that the Scots are now the superior team.
Ireland and France are huge obstacles, and perhaps they're unassailable, but it's the best shot Scotland have had since the 1990s to win the Six Nations.
Finn Russell, naturally, remains 'one to watch' ahead of kick-off, but Duhan van der Merwe is undoubtedly a superstar in his own right.
Predicted finish: 3rd
Squad
Backs (14): Fergus Burke, Matt Currie, Jamie Dobie, Darcy Graham, George Horne, Rory Hutchinson, Huw Jones, Tom Jordan, Blair Kinghorn, Stafford McDowall, Finn Russell (co-capt.), Kyle Rowe, Duhan van der Merwe, Ben White
Forwards (22): Ewan Ashman, Josh Bayliss, Jamie Bhatti, Gregor Brown, Dave Cherry, Luke Crosbie, Scott Cummings, Rory Darge (co-capt.), Jack Dempsey, Matt Fagerson, Zander Fagerson, Grant Gilchrist, Jonny Gray, Patrick Harrison, Will Hurd, Jack Mann, D'Arcy Rae, Dylan Richardson, Jamie Ritchie, Pierre Schoeman, Rory Sutherland, Marshall Sykes
France
Boosted by the return of superstar Antoine Dupont, almost certainly the greatest player of his generation, France will be aiming to claim the Six Nations crown.
They pose the biggest threat to Ireland, and were the closest to the Irish last year - even without Dupont, who would win rugby sevens gold with France at the 2024 Olympic Games in Paris.
Certainly, the head-to-head match between the French and the Irish should be the most hotly contested at this year's tournament.
They claimed victories over Scotland, England and Wales last year, so if they are able to repeat that feat - which they're more than capable of doing - it should be the case that whoever wins between Ireland and France will win the Six Nations.
With the return to Dupont and the stability provided by their backroom staff, France will be an almost unbearable force this year.
Predicted finish: 1st
Squad
Backs (18): Theo Attissogbe, Pierre-Louis Barassi, Alexandre Roumat, Louis Bielle-Biarrey, Nicolas Depoortere, Gael Drean, Antoine Dupont (capt.), Antoine Frisch, Emilien Gailleton, Mattieu Jalibert, Nolann Le Garrec, Maxime Lucu, Yoram Moefana, Noah Nene, Romain Ntamack, Damian Penaud, Thomas Ramos, Gabin Villiere
Forwards (24): Esteban Abadie, Dorian Aldegheri, Gregory Alldritt, Uini Atonio, Hugo Auradou, Cyril Baille, Giorgi Beria, Paul Boudehent, Joshua Brennan, Georges-Henri Colombe, Francois Cros, Thibaud Flament, Marko Gazzotti, Jean-Baptiste Gros, Matthias Halagahu, Oscar Jegou, Anthony Jelonch, Maxime Lamothe, Julien Marchand, Peato Mauvaka, Emmanuel Meafou, Dany Priso, Rabah Slimani, Romain Taofifenua
Italy
The Italians don't typically have high hopes for the Six Nations.
Serial Wooden Spoon winners, they enjoyed a rather famous outing last year - in which they avoided the bottom spot and managed to get a draw against France.
The Italians also beat both Scotland and Wales and only finished below the Scots counting on their inferior bonus points.
If Wales fail to improve dramatically on their recent form, it is very likely the Italians will avoid the Wooden Spoon for a second year on the spin - and they could even jump above the likes of Scotland or England if the British nations aren't careful.
After being named 2024's Player of the Championship, 22-year-old Tommaso Menoncello remains Italy's 'one to watch' this year.
Predicted finish: 5th
Squad
Forwards (17): Simone Ferrari, Riccardo Faveretto, Danilo Fischetti, Federico Ruzza, Marco Riccioni, Lorenzo Cannone, Luca Rizzoli, Alessandro Izekor, Giosue Zilocchi, Michele Lamaro, Gianmarco Lucchesi, Sebastian Negri, Gianmarco Nicotera, Ross Vincent, Niccolo Cannone, Manuel Zuliani, Dino Lamb
Backs (13): Alessandro Garbisi, Juan Ignacio Brex, Martin Page-Relo, Tommaso Menoncello, Stephen Varney, Ange Capuozzo, Tommaso Allen, Matt Gallagher, Paolo Garbisi, Simone Gesi, Leonardo Marin, Monty Ioane, Jacopo Trulla
Schedule
Round one
Friday, 31st January
Saturday, 1st February
Round two
Saturday 8th February
Sunday 9th February
Round three
Saturday 22nd February
Sunday 23rd February
Round four
Saturday 8th March
Sunday 9th March
Round five
Saturday 15th March