As the polls close on Thursday, May 7, Wales looks set to be on course for a hung parliament and some kind of coalition.
We won't know the final result until late on Friday or even Saturday morning but with the polls suggesting many constituencies are in play we've looked at the key election battlegrounds to look out for as the votes are counted.
The last poll before voting day showed the Conservatives gaining support in the final days of the 2021 Senedd election campaign.
The results showed that while Labour would likely match their share of the vote from 2016, the party could still lose seats if the Tories perform well. The poll, conducted by YouGov, found that Plaid Cymru is likely to come in third place.
The polls this election campaign have been notoriously unstable, perhaps because this is the first time the Welsh public have had a say on who represents them in Cardiff Bay since the Brexit vote and the outbreak of Covid. We must also factor in 16 and 17 year olds having the vote for the first time ever.
It's worth noting too that some key faces stood down this year and did not stand in Thursday's election.
Each poll that comes out seems to tell a new story- the latest showed Labour up by 1% point in the constituency contest while the Tories had gained 5%.
Based on the results from the last Senedd election in 2016 and some shock results in the 2019 General Election, a small shift in support could see some key seats change hands on Friday and could prove decisive in who will find themselves in the Senedd next week.
Wales Matters delivers the best of WalesOnline's coverage of politics, health, education, current affairs and local democracy straight to your inbox.
Now more than ever this sort of journalism matters and we want you to be able to access it all in one place with one click. It's completely free and you can unsubscribe at any time.
To subscribe, click here, enter your email address and follow the simple instructions.
Some of Wales' most high-profile Labour politicians have represented Cardiff West in Parliament or the Senedd including current First Minister Mark Drakeford.
Five years ago, one of the biggest upsets in Welsh politics was narrowly avoided after dwindling Labour support nearly put Plaid Cymru’s then representative Neil McEvoy in the Senedd ahead of Mark Drakeford. Labour's share of the vote fell from 47.1% in 2011 to 35.6% while Plaid's surged dramatically- in the end Mr Drakeford won by just 1,179 votes.
The political landscape has changed significantly since then however and it looks unlikely to be such a close call on Friday. What happened in 2016 were two things came together - a well-known local campaigner getting the backing of a sizeable party. It meant that when people went into the ballot box, those who traditionally voted for Plaid Cymru backed Mr McEvoy, and he would also get personal vote from those who knew him.
With Neil McEvoy now standing for Propel and Plaid represented by a local barrister Rhys ab Owen, that vote looks set to be split. All to Labour's - and Mr Drakeford's - gain.
The only Labour-Lib Dem marginal in the 2021 election, this is probably the best chance for the Liberal Democrats to win a seat outside of Brecon and Radnor.
Former leader of Cardiff Council, Rodney Berman, is the high-profile candidate hoping to swing voters away from the incumbent, Jenny Rathbone. It will be a fiercely competitive vote based on the last two elections which Ms Rathbone has won by 38 and 817 votes respectively.
She has the advantage as the sitting member but it's likely to be close once more.
Brecon and Radnorshire
This is the very last remaining constituency seat for the Liberal Democrats in all of Wales, at both Senedd and Westminster levels.
Kirsty Williams, first elected to the Senedd in 1999 and who went on to be the party's first female leader in Wales, stepped down this year with former Mid and West Wales Member William Powell taking her place.
On paper, the Lib Dems have a healthy majority here, winning the 2016 election with 15,898 votes compared to the Tories in second place with 7,728 votes. And yet, in the past decade, both the Conservatives and Plaid Cymru have made significant inroads into the Lib Dem vote across mid-Wales and this year could see that trend continue. It's a seat the Conservatives will be realistically targeting.
The Westminister seat did go back to the Lib Dems during 2019 only to be promptly lost again by the end of the year to the Conservative Fay Jones.
Once Edwina Hart’s seat, the winning margin for Labour in 2016 fell back to the point where the Conservatives are within touching distance this time round.
Last time round, Labour took the seat with 11,982 votes compared to 10,153 for the Tories. UKIP were third place then, with 3,300 votes so the result on Friday could be determined by where those votes go now they are no longer in the mix.
Since Rebecca Evans took the Senedd seat in 2016, she's risen through the ranks to hold a high-profile role in the Welsh Government as Finance Minister. She looks to have the advantage as the incumbent, but it's all to play for.
This seat has been predicted in some polls to change hands and while it isn’t a formal “target” seat for the Tories, Labour are being cautious and Ms Evans has admitted that either her Labour party or the Conservative party could win. One thing that could help Labour is that it’s not a consistent Conservative candidate fighting for the seat - in every Senedd battle it has been a different person.
In the 2015 General Election Byron Davies made history by turning the Westminster constituency blue for the first time in 105 years with just 27 votes between him and Labour. But in 2017, Tonia Antoniazzi retook it convincingly for Labour- their majority was 3,269 and it is still represented in Westminster by Labour today.
Vale of Glamorgan
On paper, this is the Welsh Conservative’s top target seat in Wales. It's one they really need to win if they are going to assert their authority over Labour’s dominance in the region.
The Tories lost out in 2016 with 13,878 votes compared to Labour's 14,655 so it's all to play for. Even in the good polls for Labour it’s being listed as going to the Conservatives.
Yet it’s also a seat marred by controversy for the Conservatives with Alun Cairns, who holds the seat at Westminster, having had to resign as Welsh Secretary in 2019 due to the actions of previous Senedd candidate, Ross England. Even so, this had little impact at the 2019 General Election.
This is a seat the party appears most confident of winning from Labour, where of longstanding Labour member Jane Hutt has a tiny 777 vote majority.
When Labour lost large swathes of the country to the crumbling 'Red Wall' at the 2019 General Election, Wrexham was a key brick in that wall.
The Tories will be aiming for a repeat of this on Friday and the Wrexham seat.
However, arguably the party's momentum since 2019 has slowed somewhat and there have been regular protests outside Westminster MP Sarah Atherton’s constituency office on a large number of issues. Plus, the Tories do have some ground to make up in the Senedd Election and will have to overcome a majority of 1,325.
Some believe the Conservatives are in for a terrible night if they fail to flip Wrexham while there is a sense from recent polls that this seat may have drifted away beyond their reach.
Vale of Clwyd
Much like in Wrexham, the Conservatives will want 2021 to be a repeat of 2019 when they swept across the north-east of Wales, picking up a large number of seats in one go.
The Tories have fought their campaign around the message that the north of Wales has been largely ignored by the Welsh Government for 20 years of devolution. Most polls predict this seat is going to change hands too.
Labour are holding on to a slim 768 vote lead and have a new candidate in Jason McLellan while this seat is held at Westminster by the Conservatives (with a majority of just 1,827).
It's a seat the Tories really need to win if they are going to halt Labour’s hopes of forming the next government. Labour could gain from the relatively short candidate list with a clear choice for voters between "them or the Tories".
Margins are likely to be very fine yet again.
Former Plaid Cymru leader Leanne Wood is defending this seat with a relatively healthy 14.7% majority (11,891 votes for Plaid compared to 8,432 for Labour). Yet Plaid has had a history here. It won Rhonda in 1999 only to lose it in 2003.
Labour has a new candidate in Elizabeth Buffy Williams and will be keen to regain Rhondda, which was one of their safest electoral seats for nearly a century before Plaid's win in 1999. The outcome of the vote on Friday will help indicate if Ms Wood's win was the start of something long-term for Plaid Cymru in the Valleys.
Plaid Cymru’s vote has started to fall back here, dropping by up to 9% at the 2019 UK election. While Ms Wood has gained popularity for her response to the floods, she is likely to see a significantly reduced majority and this seat could be all to play for in 2026.
Carmarthen West and South Pembrokeshire
In the past this has been a three-way marginal with Tory Angela Burns first elected to the Senedd in 2007 with a majority of under 100. By 2016 this had grown to 3,373 but this time round, Mrs Burns did not stand for election.
With her decision to stand down, it probably presents the best opportunity yet for Labour or Plaid Cymru to make inroads. Even so, the Tories probably have the advantage by the fact they’ve increased their grip on the Westminster seat (held by Welsh Secretary Simon Hart) and there are UKIP voters from 2016 who are likely to return to the Conservatives.
Labour is defending a healthy 10% majority here and polled nearly double the number of votes than the second-placed Conservatives in 2016. It’s the sort of seat which, if Labour lost, means they’re in for a bad result nationally.
But things are changing with previous Member Carwyn Jones, who was first elected in 1999 and who went on to become Wales' First Minister, not standing in the 2021 election. While the seat is seen as beyond the Conservatives’ grasp at the Senedd, the Tories took the Westminster seat in the 2019 General Election to the surprise of most people living outside Bridgend.
One key unknown is whether Carwyn Jones’s personal vote will be transferred to the new Labour candidate, who has a relatively low-profile. However, the Conservative campaign has not been helped by a last-minute candidate change.
It's likely the Tories have their sights set on the more realistic target of two regional list seats, rather than trying to secure a 10%+ swing in Bridgend.
Undeniably a safe seat for Labour at Westminster, at the Senedd level this is a hyper-marginal seat.
Fewer than 1,000 votes have separated Labour and Plaid Cymru at all but one of the five Senedd elections and last time round, Labour came out on top by just 382 votes - the smallest margin than any other constituency in Wales that election.
The general consensus is that Labour does better in Llanelli itself, while Plaid Cymru gain votes in the surrounding rural area and smaller towns and villages.
This may be the only place where Gwlad influences the result - just a few hundred votes could put Labour at an advantage (assuming Sian Caiach voters would otherwise have voted for Plaid).
There was a sizable UKIP vote in 2016 but even if all of that went to the Conservatives the best they could expect is third place.
This is a seat high up the Plaid Cymru target list. It’s assumed to be a straight Labour-Plaid Cymru fight, but there’s another factor that cannot be ignored: the large UKIP vote in 2016.
Plaid can be realistically optimistic - in 2016 they closed the gap between themselves and the now Labour incumbent Hefin David to 1,575 votes. Their candidate, Delyth Jewell, only needs a swing of around 3% from Labour – which is achievable.
Her campaign, albeit short, was helped by her impressive showing in the Senedd as the Member for South Wales East.
This constituency is primarily a two-horse race between Plaid Cymru and the Conservatives, although Labour is only 1,000 votes behind.
It makes this seat unusual in that both Plaid and the Tories could realistically win. Last time round, the Tories came out on top with 7,646 votes compared to Plaid with 6,892 and Labour with 6,039. Janet Finch-Saunders is the Conservative incumbent and Aaron Wynne the first time Plaid Cymru challenger.
While it's high up on the Plaid target list, the Tories are helped by the small number of candidates and a lack of UKIP and Abolish the Assembly options to split their vote.
However, on the flip side, this is probably Plaid Cymru’s best chance of a constituency gain in the region as they don’t have the likes of Propel or Gwlad standing in the constituency to split their vote.
Based on the 2016 result, you'd be forgiven for thinking this is a seat to watch in the 2021 election.
Labour won the seat in 2016 with 8,442 votes compared to a hefty 7,792 votes for Plaid, in part driven by local politics rather than a national shift.
Blaenau Gwent has developed a reputation for protest votes and given the sizable UKIP vote in 2016, this may be one of the constituencies where Abolish the Assembly does well.
Voters have also historically shown their support for Independents too – finishing in second place in 2011 – and this is unlikely to change drastically on Friday.