Christian charity Open Doors have found that the secretive believers - who face punishment if they're caught - are at greater risk during the Muslim prayer month because prayer and fasting is expected from all Saudis during the prayer month.
Beth Fuller, spokesperson for Open Doors told Premier about Ahmed, who recently became a Christian and the pressure he is facing from his family.
"They would often kind of ask him to lead the prayers during Ramadan and he finds it very awkward to say no because he doesn't really believe it anymore.
"It's quite difficult... for Christians to feel that they have that integrity in following Jesus but not making it so obvious to the people around them."
The charity said the handful of Saudis who have converted to Christianity usually keep their faith hidden as converting from Islam brings great shame on a family.
If discovered, Christians risk excommunication, imprisonment and even honour killings.
Fuller urged Christians to be praying for secret believers who need protection from people "who might be seeking to find secret Christians and expose them".
She also called for prayer over Christians in the Islamic kingdom for them to "really have wisdom as they try and work out how to keep the balance of being faithful to Jesus and yet also not revealing their faith in an obvious way".
Listen to Beth Fuller speaking with Premier's Eno Adeogun:
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