In a rare show of political unity, politicians were hoping that the UK would not hand in its membership card of the 28-nation union to form a new one-nation bloc on its own.
Riga mayor Nils Usakovs, leader of the opposition Harmony party, released the text of a letter to London mayor Sadiq Khan in which he said the vote was "the biggest decision for decades to come; leaving is a huge threat to Europe."
Foreign Minister Edgars Rinkevics from the Unity party in the three-party ruling coalition expressed similar sentiments, saying he was "keeping fingers crossed" for the Remain campaign to carry the day.
Keeping fingers crossed for #RemainINEU vote in tomorrow's UK referendum, only together we can tackle multiple challenges we all face ??????— Edgars Rinkēvičs (@edgarsrinkevics) June 22, 2016
His party colleague, MEP Artis Pabriks, drew on his background as a historian to invoke the example of Winston Churchill, who famously called for a "united states of Europe" as requirement for lasting peace on the continent.
He also called on Latvians in the UK who have British citizenship to use their mandate to back Britain's membership of the EU, saying: "I very much hope those Latvians in Britain who have British citizenship will go and vote to remain in the EU," he said.
Es ļoti ceru ka tie latvieši Britānijā kuriem ir Britu pilsonība ies un nobalsos par palikšanu ES #Brexit— Artis Pabriks (@Pabriks) June 20, 2016
Meanwhile, even Janis Iesalnieks, a controversial figure on the far right wing of the nationalist National Alliance party gave his reasoning for the UK to remain, albeit with some reservations.
Brexit būtu emocionāli patīkams trieciens eirofederālistiem, taču Latvijas interesēs ir GB kā saprātīgākās Eiropas lielvalsts palikšana ES.— Jānis Iesalnieks (@JanisIesalnieks) June 21, 2016
"Brexit would be an emotionally pleasant blow to eurofederalists, but as Britain is a sensible, major European state it is in Latvia's interests for it to remain in the EU," he wrote.
Meanwhile national broadcaster LTV has launched a twitter poll asking people if Britain should remains part of the EU (Ja) or should leave (Ne) so even if you are not a confused Brit you can have your say.
Rīt, 23.jūnijā, briti izdarīs izvēli - palikt vai izstāties no ES. Vai britiem vajadzētu palikt ES sastāvā?— LTV Ziņu dienests (@ltvzinas) June 22, 2016
Britons go to the polls Thursday with results expected on Friday. Pollsters say the result is expected to be close.