Ireland and Leinster still out to disprove notion of Lions hangover

2025 WAS A strange year in Irish men’s rugby.

There were some obvious highs. A record number of Irish players and coaches drove the Lions to a series success in Australia. Ireland claimed the 14th Triple Crown in their history. Leinster ended their trophy wait by winning the URC, beating the Bulls emphatically in the final. Munster and Connacht landed high-profile, highly-regarded head coaches, while Ulster brought in a couple of big-name signings.

But then there was Ireland’s poor finish to the Six Nations after winning that Triple Crown. There was Connacht and Ulster 13th and 14th in the URC, while Munster were knocked out in the quarter-finals. Leinster underperformed as they were rocked by Northampton in the Champions Cup semi-finals. The Ireland U20s finished last in the Six Nations and narrowly avoided the same position in the Junior World Championship. And Ireland’s autumn was bookended by a damp squib against New Zealand and a scrum battering at the hands of South Africa.

It’s impossible to disentangle one of those big highs — the Lions tour — from how the year ended with Ireland’s disappointing autumn campaign.

The majority of the Irish players who were central to the Lions tour under Andy Farrell played just once for their provinces, mainly Leinster, before returning to international rugby in the game against New Zealand in Chicago. 

Clearly, that’s not the best preparation for playing at the highest level. Farrell and co. insisted it couldn’t be an excuse before facing the All Blacks, but they have since agreed with everyone else that it was a reason for the Irish underperformance.

It’s worth noting here that Ireland’s form in November 2025 was similar to their form in November 2024 and their inconsistent performances in the 2025 Six Nations. So it’s not exclusively a post-Lions thing.

But it would be fascinating to get Farrell’s honest, unfiltered thoughts on how he looked at things post-Lions when he decided to bring such a large cohort of his Irish players on tour to Australia.

Firstly, it extended those players’ seasons by a few weeks but also taxed them even further in a physical sense because a Lions tour is so hectic with constant changes of location and games every few days.

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There tends to be a hefty mental toll too, given the relentlessness of such a long tour with a big Test series at the end of it. The second Wallabies clash in front of more than 90,000 people in Melbourne might go down as the biggest game of some players’ careers.

All of this is to say that the notion of a Lions hangover is nothing new. There have been plenty of players in the past who have struggled physically and/or mentally to get back to their best the season after being on a Lions tour.

Yet there isn’t always such a big contingent from one country as Ireland provided for the 2025 version.

Warren Gatland did bring a big cohort of Welshmen on the 2013 Lions tour and they weren’t great the following season, losing to South Africa and Australia in the autumn that followed and then relinquishing their Six Nations title in 2014 as they finished third.

Farrell must have known that Ireland’s autumn series would be affected by the Lions tour, but his primary goal was to win the series against the Wallabies and he believed that a big group of Irish players could help him to do that.

His belief must also have been that the experience of touring Australia and beating the Wallabies in such a high-profile series was massively worth it for the big Irish contingent in the long-term. Many of the same players and staff will be back in Australia trying to win the 2027 World Cup.

But everyone would obviously have hoped that there would be no Lions hangover for Ireland or for Leinster, who provided a record number of players from one club for the tour of Australia.

Back in September, before the season kicked off, Leo Cullen was asked about this. It was put to him that players who go on Lions tours can have disrupted seasons and struggle to be at their best.

“I’ve never heard that,” said Cullen with a smile.

“I need to get that report. Who’s done the actual study of that?”

But it’s obviously something that Cullen and Leinster had considered and possibly worried about.

The same day, he confirmed that Joe McCarthy and Hugo Keenan would be sidelined for the new season after undergoing surgery following the Lions tour.

It could be that their extended time out of action has been a blessing in disguise. After missing the autumn Tests, McCarthy has returned to action for Leinster in December in energetic, explosive form, while Keenan is due back in the New Year and could benefit from the chance to finally deal with a hip issue and any other niggles he had been carrying while playing a lot of top-end rugby in the last few seasons.

“We just have to prove that wrong,” said Leinster boss Cullen when asked about Lions hangovers a second time.

And that’s what Leinster and Ireland both need to go about doing in the remaining six months of this season.

The majority of the Ireland squad were not at their best in the autumn, so Farrell will push them to peak for the Six Nations and again for the Nations Championship clashes with Australia, Japan, and New Zealand in July.

Farrell will also be pushing himself to be on top of his craft as Ireland’s boss. The Lions tour is hugely challenging for the head coach, with so much going on with games, training, recovery, and travel, as well as all the additional scrutiny. As with his players, Farrell will surely feel like he didn’t deliver his best work in the autumn.

Cullen, meanwhile, will be pushing many of the same players to be in peak condition in May when the Champions Cup semi-finals and final take place, then on into June for the URC play-offs.

No pressure.