The Labour Ministry said the number of people filing for unemployment benefits fell by 98,853, or 2.1%, compared with the previous month.
June is generally a good month for employment as it marks the beginning of the tourist season.
Despite the fall, the unemployment rate in Spain is still the highest in the eurozone.
According to EU figures published on Monday, one in four of the Spanish workforce is out of a job, compared with an overall rate of unemployment for the 17-member bloc of 11.1%.
"June is traditionally good for the unemployment queue but we have never reached a decline of nearly 100,000 people," said Spain's state secretary for labour, Engracia Hidalgo.
"We will have to follow the development of the unemployment figures after this good data for June to verify whether we are turning towards a positive trend."
June is the third month in a row that the number of unemployed has fallen in Spain. In March, the number of jobseekers hit a record high of 4.75 million.
The Spanish government is implementing a number of labour market reforms to try to reduce unemployment, including cutting back on severance pay and restricting inflation-linked salary increases. These have proved very unpopular with unions and workers.
However, it has been forced to approve billions of euros of spending cuts and tax increases in an effort to reduce its debt levels, which have had a negative impact on employment within the economy.

The leaflets said the patient had been referred for an urgent appointment as their symptoms might indicate cancer.
East Sussex NHS Trust has put the mix-up down to an external company that distributes its printed material.
It said the wrong patient information leaflets were added to hospital appointment letters sent out in March.
It has now contacted everyone affected to apologise and explain what went wrong.
Liz Fellows, assistant director of operations at the trust, said: "It was an administrative error and we apologise for any unnecessary anxiety this error may have caused."
East Sussex Healthcare NHS Trust covers Hastings, Eastbourne and Rother, and is responsible for the Conquest Hospital and Eastbourne District Hospital.
The trust said that due to the large number of appointment letters it sends out it uses an external printing company to print and distribute appointment letters.
It said each letter is coded to indicate any supplementary information that needs to accompany it.
Ms Fellows said: "Unfortunately, for a short period in March, the printing company inadvertently miscoded approximately 850 letters resulting in a 'two-week information leaflet' being inserted with an appointment letter.
"As soon as the error became apparent it was stopped immediately, and letters of apology sent out."

Yvonne Mosquito, the West Midlands Deputy PCC, was suspended after visiting a murder victim's family without informing officers.
Following a disciplinary in May 2016, Ms Mosquito had an employment tribunal listed to take place in May 2017.
A joint statement said "all outstanding matters" were resolved.
A BBC source said Ms Mosquito had received a payout. The Office of the Police and Crime Commissioner said it would not comment on whether money had exchanged hands.
Allegations against Ms Mosquito related to a visit she paid to the family of Kenichi Phillips, 18, who was shot dead in a car in Birmingham, on 17 March 2016.
Police and Crime Commissioner David Jamieson said her actions "caused ongoing upset and distress" and "damaged the relationship" between the family and police "in the middle of a complex and sensitive murder investigation".
Her supporters insisted she visited as an ordained minister who wanted to offer condolences to relatives.
Her union Unite rejected the allegations, saying it was "deplorable" the hearing went ahead in Ms Mosquito's absence.
She was issued with a final written warning and her contract was never renewed.
The BBC previously reported Ms Mosquito wrote a letter of complaint about the PCC's behaviour towards her, of which the PCC was aware, four weeks before her suspension.
A joint statement issued by the Office of the Police and Crime Commissioner (PCC) and Ms Mosquito said they were "happy to announce that they have amicably settled all outstanding matters between them".
"Litigation is a stressful business and the parties acknowledge and regret the effects that inevitably follow from that," it added.
The former colleagues thanked each other for their work around issues of equality, the statement added.
The number of people looking for work in Spain fell almost 100,000 in June, a record for the month, to 4.62 million.
[NEXT_CONCEPT]
Hospital bosses in Sussex have apologised after about 850 patients were sent leaflets in error suggesting they might have cancer.
[NEXT_CONCEPT]
A row between a Police and Crime Commissioner and his deputy, who was found guilty of serious misconduct, has been resolved following a payout.