Hi, my 4.5month old has been rolling from back to tummy for about 2 weeks now, can go both ways. He sleeps in his bassinet, in an arms out sleeping suit. We are making the transition to the cot now and are starting with supervised day sleeps. I have observed he will roll onto his side in the cot. He is not yet independently consistently rolling from tummy to back (has done a couple of times though), however once on his stomach we always observe him to either turn his head to the side, raise his head up (does this very well) or make a lot of noise if he’s trying to suck his hand (and indicate he’s hungry). Can you please advise if this is safe to continue with? I’m quite nervous about putting him in the cot overnight if he happens to roll. Would love some guidance. Thank you

Most babies will be rolling over by 4- 5 months. Some earlier, some later.
This is very normal as babies grow & become stronger.
Many babies then prefer to sleep on their side or tummy.
This is not something that needs to be stopped. It is important to make the “new” environment as safe as possible.
https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over

Once baby is rolling, it is important that all babies have their arms free (no swaddling/wrapping) & the space of a cot.
Also important that he is now transferred to a cot for all sleeps to allow him the space to roll well.
Many babies like to touch their face &/or suck on their fingers as part of self settling.

Still always place him on his back for sleep.

If he is able to roll easily both ways, when he does roll, he can be left in his position of preference, after being placed on his back.
This is only if his environment is as safe a is possible, as described above - arms free & the space of a cot.

How does he go with tummy time when awake?
Increasing tummy time helps with increasing upper body strength which also aids the ability to roll well.

Hello, just an update to my original question below. Our son has now been in the cot the last 4-5 nights. We always place him on his back in his safe sleeping bag, arms free, in the middle/bottom of the cot. We notice he always rolls to the right (in bed, during play can also go left) and whilst occasionally sleeping on his side and back, primarily seems happiest on his stomach to sleep. He is able to turn his head to the side. He is very competent at rolling back to stomach, and has definitely been doing more rolling tummy to back during play (although not always but more than he was a week ago) however when in bed, doesn’t tend to do this. When he wakes he often raises his head in the tummy time position- very strong @ this, and/or makes a noise.
I am continuously waking to check on him & find him on his stomach to sleep. So I reposition back to his back, but sure enough he returns back to his stomach again within 10mins. Do I need to continuously keep waking and returning him back, or based on above, it’s ok to leave him as is? Thank you.

Sounds like he is mastering his rolling. This is all very normal & once babies find their tummy to sleep, they tend to prefer to sleeping on tummy or side.
You have made all the necessary adjustments for his new sleep environment - in a cot, arms free & ensuring mattress is firm & flat with nothing loose or soft in the cot. He is also able to roll both ways & hold his head up well.
Still keep placing him on his back for sleep & let him find his own position of comfort.

You are not expected to sit up at night watching him sleeping, or to keep rolling him back now. As you have said, he soon goes back to his tummy for sleep.
*** https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over