Zip’s Mailbox Club › The Wonder Library
Published September 17, 2026
The Adventure Letters mails a child two story letters a month that teach U.S. geography through a travelling pen pal character, for $12.99 a month. Zip’s Mailbox Club mails two personalized mail deliveries every month from Zip, a stamp who lives in the mailbox, and Zip writes back to what the child says. Both land twice a month. The real difference is what the mail is for: a geography journey the child reads, or a letter written to that specific child that answers what they send back. Full disclosure, we make one of these two, so read this as a maker’s map of the field and not a neutral review site. Everything below about their service was read off their own website on September 17, 2026. Check theirs before you buy.
Zip includes a pre-stamped envelope with each mailing: one to reply to Zip, and one to write to a friend. Replies are optional.
Choose The Adventure Letters if you want U.S. geography delivered as a story to a child of 8 or older. Their site describes two letters a month for a year, a pen pal character touring the Eastern or Western states, and extras such as stickers, scrapbook pages and conversation cards. It costs less than we do, and for a grade 3 to 5 geography year it is a very good fit.
Choose Zip’s Mailbox Club if you want the mail to be about your child and to answer them. Two personalized mail deliveries every month, written to your child by name about the things they actually love, with a pre-stamped envelope in every package, and what your child writes back shows up in a later letter.
| The Adventure Letters | Zip’s Mailbox Club | |
|---|---|---|
| What arrives | Story letters from a pen pal character travelling the United States, with stickers, scrapbook pages, conversation cards and what they call the occasional mystery gift | A letter from Zip, a new Mailbox Crew friend, and a year-long mystery, plus a second delivery about two weeks later |
| How often | 2 letters a month for a year, sent every 2nd and 4th Friday | 2 mail deliveries a month (24 a year) |
| Price as listed | $12.99 a month, or $150 to prepay the year, free U.S. shipping | $20 a month, or $200 for a prepaid year |
| Ages | Stated as ideal for ages 8 to 13, with the Western States series written for older children | 3 to 12, with the writing matched to the child’s reading level |
| Personalization | Their site calls the letters personalized and describes an envelope addressed to the child. It does not describe letters built around the child’s own interests | Name, age, and the child’s own interests and replies shape the letters |
| Child writes back? | Not described on their site | Yes. Stamped reply card in every package, and Zip remembers what the child writes |
| Main purpose | Learning U.S. geography, state by state | A personal, two-way friendship by mail and one year-long mystery |
Sourced from theadventureletters.com and this site, September 17, 2026. Terms change, confirm on their pages.
Their own words: “Subscribers will receive 2 letters a month for a year, billed monthly for $12.99/mo.” The letters follow a pen pal character across the country. Their site lists two journeys, the Eastern States and the Western States, and describes landmarks, cities and historic sites along the way, with extras such as stickers, scrapbook pages, conversation cards and the occasional mystery gift. They say the Western States series adds a further learning page and bolded key words for children who want to look things up.
That is a geography unit delivered slowly, on purpose, and it is a smart idea. Their site also says yearly subscriptions can be bought with Education Savings Account funds, which tells you who it is built for: parents who want the mailbox to carry part of the school year.
Not as part of the subscription, based on their own site as read on September 17, 2026. The letters come from a pen pal character, but we looked for a described way for a child to reply and be answered, and did not find one. The mail travels one way, from the story to the reader, which is a perfectly reasonable design for a learning supplement.
Zip’s is built around the other half of that loop. Every package includes a pre-stamped envelope, and when a child sends something back, a scribble, a drawing, a dictated sentence, or a full letter, that detail is remembered and shows up in a later letter from Zip. We wrote about the difference that makes in what happens when your child writes back.
Both use the word, and they mean different things by it. The Adventure Letters site speaks of a “personalized letter” and of an envelope addressed to the child. We found no description of the story itself changing from one subscriber to the next, or of letters written around a child’s own interests. The journey through the states reads as the same journey for every subscriber. If that distinction matters to you, ask them directly rather than taking our reading of their site as final.
Zip’s letters start from the child. Their name, their age, the dog, the best friend, the obsession with sharks, and then their own replies, which is why two children in the same family get two different envelopes.
The Adventure Letters lists $12.99 a month, or $150 to prepay the entire year, with free domestic shipping in the U.S. Their site says they do not currently ship internationally. On price alone they are the cheaper of the two, and we would rather say so plainly.
Zip’s Mailbox Club is $20 a month, or $200 for a prepaid year. That covers two personalized mail deliveries every month for one child, which is 24 mail moments a year. The prepaid year works out to about $16.67 a month. See our pricing page for current details. If you want the whole category laid out by price, we keep that in how much a kids mail subscription costs.
Their site says the letters were designed with upper elementary students in mind and are ideal for kids between ages 8 and 13. They tie that to the U.S. geography most children study in grades 3 to 5, and say the Western States series was written with older children in mind.
Zip’s Mailbox Club serves ages 3 to 12, with the writing matched to the child’s reading level. A three-year-old gets a letter a grown-up reads aloud, with pointing and marking and dictating as the way they answer. A ten-year-old gets more words, more plot, and clues they can work out alone. If your child is younger than 8, that is the deciding fact between these two. We go age by age in mail for 8-year-olds and mail for 9-year-olds and up.
Pick The Adventure Letters if any of these describe you. Your child is 8 or older and you want geography in the mix. You homeschool and want a supplement that arrives on its own schedule. Budget is the deciding factor. Or you have several children at different levels who will read the same letter together, which their site says the letters suit well.
Pick Zip’s if the mail being personal is the whole point. You want letters that name your child’s actual dog, actual best friend, actual obsession, and that change as those things change. You want your child to write, and to be answered, so the mailbox becomes a conversation rather than a delivery. Your child is anywhere from 3 to 12. Or you want one continuing story that bends around your own child.
Zip’s Mailbox Club launched in July 2026. Zip writes to your child by name every month and answers what your child sends back. You can see how it works, or read how it fits a school-at-home week in letter subscriptions for homeschool families.
If neither of these two is quite right, the category has other shapes. Sunny the Mail Snail sends weekly letters from a travelling snail, which suits a younger child who measures the week in mail days. The Max Letters sends two chapter letters a month telling one fantasy adventure. Little Letters Club from Growing Up Littles sends a monthly themed mailing. Activity boxes send kits and crafts instead of letters entirely, which suits a builder more than a reader.
We lay all of them out together in our comparison of kids’ letter subscriptions, and if you are still deciding whether this whole category is for you, start with snail mail for kids.
Not as part of the subscription, based on their own website as read on September 17, 2026. Their pages describe story letters from a pen pal character travelling across the United States, with stickers, scrapbook pages and conversation cards. We did not find a described way for a child to send a reply and be answered. Zip’s Mailbox Club is built the other way around: every package includes a pre-stamped envelope, and what the child writes back is remembered and used in later letters.
Their site states that subscribers receive 2 letters a month for a year, billed monthly for $12.99 a month, or $150 to prepay the entire year, with free domestic shipping in the U.S. That was read on September 17, 2026, so confirm on their site. For comparison, Zip’s Mailbox Club is $20 a month or $200 for a prepaid year.
Their site says the letters were designed with upper elementary students in mind and are ideal for kids between ages 8 and 13, and that the Western States series was written with older children in mind. Zip’s Mailbox Club serves ages 3 to 12, with the writing matched to the child’s reading level, so it reaches much younger children.
Twice a month. Their site states that letters are sent every 2nd and 4th Friday of each month and arrive within 2 weeks after shipping, within the U.S. only. Zip’s Mailbox Club also sends two personalized mail deliveries every month, which is 24 a year.
It depends on what you want. If you want U.S. geography taught through story letters for a child of 8 or older, The Adventure Letters is aimed squarely at that. If you want mail that is about your own child and answers them, Zip’s Mailbox Club is $20 a month or $200 for a prepaid year, for ages 3 to 12, with two personalized mail deliveries every month.
Zip’s Mailbox Club. The Adventure Letters states an ideal range of ages 8 to 13 and ties the letters to the U.S. geography most children study in grades 3 to 5. Zip writes to a three-year-old in a form a grown-up reads aloud, with pointing, marking, and dictating as the way the child answers back.
Each month brings a letter from Zip and a second letter from that month's Mailbox Crew member. Your child's replies can shape a later letter, so the story remembers what they share. Behind the scenes, Zip's Mailbox Club was founded by Mack, a dad who writes, personalizes, and hand-packs the mail behind these guides. Read the founder story →
Personalized real mail for your child every month, a letter from Zip, a new Mailbox Crew friend, and a year-long mystery only your child can help solve.
Join the Mailbox Club →A collection of essays about childhood, curiosity, imagination, and slowing down.