The discovery is being described as one of the most significant in Britain in recent years.
The coins - over 1,000-years-old - were unearthed during a Christmas dig organised by the Weekend Wanderers Detecting Club on farmland near Aylesbury, Buckinghamshire.
Over 100 people turned out to take part in the festive hunt and they were stunned to find the collection of more than 5,000 silver coins.
The perfectly preserved pieces, which feature the faces of Anglo Saxon kings, were in a lead bucket, buried two feet underground.
Experts said the extremely rare coins could be worth more than £1m and club leader Pete Welch said the find was “very significant”.
Mr Welch, 56, said: “They’re like mirrors, no scratching, and buried really carefully in a lead container, deep down.
“It looks like only two people have handled these coins. The person who made them and the person who buried them.
“Metal detecting is a bit random but most farms have a bit of history so you have a chance of finding something.
“I think this was a case of you either move to the right or move to the left and on this case our member moved the right way.
“I’m just hoping that these coins will end up in a museum for the public to see. I wouldn’t want to see them go to a private collector.”
The discovery of a total of 5,251 coins was made during the annual dig on December 21 on farmland the group had visited before.
After they were found archaeologist Ros Tyrrell was called to help excavate them.
The coins are in “superb condition” and show the faces of some of the kings of England dating back 1,000 years.
They include coins from the reigns of Ethelred the Unready (978-1016 AD) and Canute, or Cnut (1016-1035 AD) famous for the legend of holding back the tide.
Mr Welch believes the hoard is equal in importance to the Staffordshire Hoard of gold and garnets found by a metal detectorist in 2009.
He added: “We don’t know how many variations of the coins there are and when we do we will know how significant the find is.
“This would have been a huge amount of money in its day. One coin alone would have been a lot back then.
“Everyone dreams of a pot of gold. The reality is you spend most of your time digging up bits of junk
“This is the first of its kind since I’ve been running the club, which is 23 years.”
A Bucks County Museum spokesman said: “This is one of the largest hoards of Anglo Saxon coins ever found in Britain.
“When the coins have been properly identified and dated, we may be able to guess at why such a great treasure was buried.”
As the coins are precious metal over 300-years-old they fall within the remit of the Treasure Act.
After conservation and identification at the British Museum a coroner will decide whether they are legally treasure.