Can I open a sealed letter early?

No — sealed means sealed, even for the writer; the letter opens only on the date you chose.

Until what date can I seal a letter?

You pick the opening date freely — popular choices are the first birthday, the first day of school and the 18th birthday.

Can grandparents or the other parent write letters too?

Both parents write in the shared diary, and a grandparent's words can be captured and sealed together with them.

Are the letters private?

Yes. Lunita shows no ads, doesn't track you and doesn't sell data; a sealed letter stays locked for everyone until its opening date.

What if I don't know what to write?

Write three true sentences about today — and borrow a template plus twelve prompts from our guide "Letter to your baby."

How do I write a letter to my baby that they'll read years from now?

Q: Does the letter feature cost anything?

No, letters to the future are part of the permanently free diary core — Premium features are optional.

Write the letter today and seal it until a date you choose — the first birthday, or the eighteenth. In Lunita these are called letters to the future: once sealed, a letter is locked for everyone, even the person who wrote it. It opens only on the chosen day — a true time capsule made of words.

Why a letter is different from a diary entry

A diary tells what happened. A letter speaks to someone. When you write to your baby — "You're asleep on my chest right now, and I can't stop looking at you" — you're not writing about your child, you're writing to them. To the person they will one day be. That changes the voice entirely, and it's exactly what makes these letters so precious later: one day your child will read how you talked to them when they were three weeks old.

Sealed means sealed — even for you

The heart of Lunita's letters is the seal. You write, pick an opening date — the first birthday, the first day of school, the eighteenth — and seal the letter. From that moment it is locked: for your partner, for the family, and for you too. No peeking, no going back to polish the sentences you wrote that night.

That sounds strict, but it's the whole point. A time capsule only works if it's actually closed. The letter stays exactly as honest as it was at 3am — tired, overwhelmed, head over heels. That rawness is what brings tears eighteen years from now.

Occasions worth a sealed letter

At birth, opening on the 18th birthday — the classic: who you were, what you hoped for them, what the world looked like
For the first birthday — written in the first weeks, read when the year is done (it's a letter to your future selves, too)
From Grandma and Grandpa — the grandparents' words, kept safe for a day when they'll be priceless
Before a big transition — a move, a sibling, the first day of daycare: capture what it was like before
During pregnancy — to your unborn child, sealed until their first birthday (more on the page for expecting parents)

"I don't know what to write"

Almost everyone feels that before the first letter. The good news: the letter doesn't have to be literary, it only has to be true. Three sentences about this particular Tuesday beat any greeting-card prose. Write how your day went. What your baby did today for the first time. What you're afraid of and what you can't wait for. If you'd like a head start, our guide letter to your baby has a template and twelve concrete prompts.

Letters as part of a bigger story

In Lunita, letters don't stand alone. They belong to a private diary both parents keep together — with daily duet questions, photos and a firsts board. Letters to the future are part of the permanently free diary core; Premium features like monthly stories and photo books are optional. And because a letter to your child is among the most private things there are: Lunita shows no ads, doesn't track you and doesn't sell data — see the private baby diary app page. How you write together as a couple is covered in Lunita for both parents.