Jack Letts, 20, from Oxford, dubbed "Jihadi Jack" by some newspapers, is said to have left for Iraq aged 18.
John Letts and Sally Lane were remanded in custody accused of providing money for suspected terrorism.
The judge said they were "perfectly decent people" who ended up in custody "because of the love of their child".
But the pair were remanded in custody on Thursday and granted bail earlier when they appeared at the Old Bailey.
Mr Letts appeared via videolink from HMP Wandsworth, with his arm in a sling fashioned from a jumper to protect an old injury that had flared up in jail.
Defence barrister Di Middleton said the effect of a few days behind bars had been "incalculable" for both of them.
She promised the judge the pair would not attempt to send any more money to their son and had not done so while on police bail which was granted earlier in the investigation.
Judge Mr Justice Saunders warned the couple that if they breached the terms it would be "extremely unlikely" for it to be renewed.
Mr Letts, 55, and Ms Lane, 54, are both accused of transferring £223 on 2 September last year, £1,000 on 31 December 2015 and £500 on 4 January 2016.
The couple, of Chilswell Road, Oxford, are charged with three counts of arranging the availability of property or money to another person, knowing or having reasonable cause to suspect it could be used for the purpose of terrorism.
Ms Lane is charged with two further counts of attempting to provide money or property knowing or having reasonable cause to suspect it could be used for the purpose of terrorism.
On Thursday,  Westminster Magistrates' Court heard she attempted to send two payments of £500 to her son on January 4 2016.
Jack Letts, 20, is suspected of being the first white Briton to join the terror group after he left his Oxford home and travelled to Syria last year.
The couple are next due to appear at the Old Bailey on June 23.
The parents of a man alleged to have joined so-called Islamic State group have been granted bail after they were charged with terrorism offences.