I see no reason to assert any belief or non-belief until a need arises to do so.
ETA: When the need arises, simply state the truth of who you are and what you believe or not believe. I personally do not use the word atheist because of the negative connotation that it carries and non-believer, based on lack of evidence, facts and data, is just as true.

Don't "admit" it. Profess it with pride.

I used to just wear my Limp Wrist band shirt that said in large letters FAGS HATE GOD. Pretty sure everyone knew how I felt about religion

Honesty, if they truly love you, then not an issue. If you cannot be honest with family and friends, then there is something wrong. There is no shame at all.

There was an occasion where I was with family, visiting my great-uncle.
We were sitting around the dining room table, having "cake and coffee".
The discussion turned to religion.
I sat quietly for a while, just listening.
When I got my bellyfull of all the self-righteous pronouncements, and gossiping
about their friends and neighbors, and attention turned to me because I'd been
so uncharacteristically quiet, I knew it was now or never.
"I'm an unapologetic atheist."
My great-uncle reached over and took my hand, and told me that he was, too.
The general consensus was that they were all far more surprised by his admission
than they were by mine.
He was 92 at the time, and he lived to be 102.
The family held a catholic funeral for him, because that was what THEY wanted.
I didn't go.

You can only be true to yourself. If you feel like you can't keep up the charade just
to make other people happy, only you will know when it's time to stop.
I didn't worry about their responses to my atheism. I didn't care how they felt about it.
It had nothing to do with them. They were still free to believe any bullshit they pleased. I just let them know I wasn't going to play along anymore.
Most of them don't talk to me, which is no great loss.
I have never lived for the approval of my family.
I learned at the VERY early age that it was likely that I'd never have it anyway.

If I have any advice to give, it is to do what makes YOU happy.
What other people think often has very little to do with what makes you happy, and almost everything to do with what they think you should do to make them happy.

Good luck.
Be bold.

Each situation is different, but you might just start by not compromising your beliefs whenever the subject of religion comes up. Stay true to yourself, and if you are asked to participate in a religious activity, explain why you'd rather not, honestly. Hints over time soften the news.

If you have a particular family member who you feel would be especially shocked to know of your non-belief, you might want to set aside some time to present the subject softly and personally, expressing that you understand that they might react negatively to the news.

If it's a big thing, the news will spread quickly. Some folks might tell them it's not a big deal, some folks might tell them to dis-own you, but whatever the outcome, just present it in the most humanely way possible and underscore how you've come to your conclusion thoughtfully and do believe in the beautiful human virtues of love and compassion, and so on, but just not that those virtues are solely religious virtues.

You might be surprised to find out that many people don't care all that much about your spirituality, as long as you don't try to push your views on them, and you stand firm when someone tries to push their views on you.

You might read (or listen) to books written on the subject, such as "Coming out Atheist" by Greta Christina, for great advice.

You don't have to , "admit ," anything at all . You're not breaking any law . People change over time .

“This above all: to thine own self be true
And it must follow, as the night the day
Thou canst not then be false to any man/Farewell, my blessing season this in thee!”
William Shakespeare, Hamlet

I'd just add: but don't be a jerk about it.

There are some good t-shirts.

Admit? you start with the premise that you are in the wrong - but in reality there is no right or wrong - people believe what they believe and don't believe what they don't believe. Just tell them that when it comes to mystical beings like a god you do not believe it exists. ... may be worth pointing out that religion is not mandatory to belief in morals and ethics.

I would avoid the whole, "I have come to the realization that you are a flaming lunatic!" conversation!

Be honest, be genuine, be heartfelt. Let them know that you still respect their beliefs as you expect yours to be respected.

I was quite open about it. I heard people saying I'm going to pray for you. this that and the other. Didn't change a thing for me. I honestly don't care. so everyone in my family, friendship circle and workplace know. I openly raised my kids that way too.

My take - tell your family and friends. People who love you for who you are will stay. Don't declare at work. Don't make things difficult for you. They are just work colleagues. Nothing more. They don't have to know about your personal beliefs and you don't need to know theirs.

Don’t make it a big thing. Personally for me it just came out in conversation and with my family we just kept the conversation going. I know it isn’t as easy for everyone else. Just start off by not bowing your head for dinner prayers and stop saying god bless you. Let the conversation come to you

Probably just say “Hey, friends, family and co workers, I’m a non-believer!”

A lot of LGBT+ people do it. Take courage from their decision and free yourself from the shackles of fearful conformity.

wait until the issue comes up from members of your family, friends or coworkers, don't volunteer the information when nobody asks you, and when the issue comes up just say very matter of factly that you don't believe in any religion, period. Up to them how they react, don't explain, just say that you don't believe, most non family will just mind their own business, family is another matter, some will try to make you feel guilty or convert you, just say, please respect my beliefs, I have never questioned your beliefs have I? or something of that nature, that should stop them.

I try to handle it the way I would handle the topic of Santa Claus around any four-year old... with love.

"not so much anymore" was a phrase that helped me. softens the blow.

"hey pop, you still got faith?"
"of course what are you talkin' about? don't you?"
"not so much anymore"

I just started telling them but I tried not to step on their toes. if it was making them happy then good for them. it just didnt fit me.

i don't understand the "admit" aspect of it, but if you feel they would disapprove, then there is nothing you can say that will make them approve and if you think they need to know, then just tell them, bluntly. the more you apologize, the more you give them the idea they can threaten or cajole you back into the fold. the less importance you show that it has for you, the less hold they have on you.

g

Show that some of the problems that have genuinely troubled your family [can't go through all possibilities) can be solved by your sort of thinking. A different slant on explanations can work wonders.

I don't broadcast that I'm an atheist but I might say something to an individual depending on the conversation. Let the conversation and situation determine who knows. After a while everyone will know--people like to gossip.

The best way? Don't....

Sometimes I just say Im agnostic. I told a Frere a long time ago that I didnt feel comfortable saying the confession of faith. I said if there is a god, i don't think god would want me to lie. Im not sure you need to tell everyone. Its personal, as you said yourself. What makes you want to share your beliefs or what you don't believe?

Like a band-aid, but there's no need to make a scene out of it. They are tge ones with the weird position. You're just being logic.

I "study" religions from a scientific, objective point of view. I don't "drink the coolaid" but rather see it as a social aspect of societies and the human need to couple, group, and have a social narrative. So I have no interest in their scriptures and moral rules based on a book of sayings.

While I won't disrespect them outright. I do keep an objective perspective and listen "for science" the behaviors and mental illness of those afflicted. It is important to not let the hoard know you are not one of them as this will ripple through the community.

Sometimes I like to reference passages from the Koran, Satanic Bible, or Hindu texts as a comparison. But much of that feels tiring after a fashion and I just let it be.

Silent Observer seems to suite me best.