EXCERPTS
Previously parents could receive 600 hours of free childcare - roughly 16 hours per week in term time.
In August this increases to 1,140 hours a year for all three and four-year-olds, and a quarter of two-year-olds.
It is part of a "landmark" £1.5bn funding deal between the Scottish government and local authorities.
Children's minister Maree Todd said the new scheme could save each family as much as £4,500.
However critics of the scheme have raised issues over cost, timing and a "workforce crisis" in nurseries.
In 2017 the Scottish government announced it would almost double its funded childcare as part of a plan to reduce health, education and employment inequalities later in life.
Spending watchdog Audit Scotland later warned of a "significant risk" that local authorities would not be able to fund the expansion.
However the government and Cosla reached an agreement two months later. It set out plans to spend £990m on day-to-day funding for the scheme by 2021 - £150m more than the government's previous estimate.
Opposition politicians had previously warned of a £160m "black hole" in the funding proposals.
Funding will rise annually from £33m this financial year to £567m by 2021/22, totalling £1.5bn over five years.
The National Day Nurseries Association (NDNA) produced research last year which showed 71% of employers struggled to recruit staff at practitioner level - and that Scotland's nursery staff turnover rate was 29%, higher than the UK average.
It recommended the scheme be reviewed annually to ensure nurseries could cover the cost of the new offer as well as keeping staff.
'Confidence boost' for children
Since March 2018 more than 270 nurseries have been built, extended or refurbished and an additional 4,300 full time equivalent staff are in post, according to the Scottish government.
A phasing system was implemented last year giving approximately 50,000 children 1,140 hours of funded childcare ahead of the national rollout.
Ms Todd said this was to enable parents to explore work, training or education opportunities.
She said: "Tens of thousands of children are already benefitting from high-quality early learning and childcare, and I've heard first-hand how it's helped to boost their confidence and communication skills, and given them access to more opportunities such as outdoor learning.
"I've also heard how it has made an enormous difference to families in terms of enabling mums and dads to get back into, or spend more time studying, working or training."
How do parents apply?
Each council has separate application processes and deadlines.
Parents or carers can register through their local authority and apply for the option that suits their needs from the choices available.
This could be a council, private or third sector nursery, playgroup or childminder.
The Parent Club website will link to your local authority for more information.