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Can You Mail Coloring Postcards After Coloring Them?

Yes, many coloring postcards can be mailed after coloring, but only if the finished card still meets current postal standards and remains flat, legible, rectangular, and free of problematic attachments. Use dry colored pencils when mailing matters, keep the address side clean, avoid bulky embellishments, let gel pens dry fully, and put important cards in an envelope if you are unsure.

Published September 11, 2026Source-checked editorial guidance

Yes, but the finished card still has to behave like mail

You can often mail a coloring postcard after coloring it, but the colored art does not override postal rules. The finished piece still needs to be the right general size and thickness, readable on the address side, flat enough for processing, and free of decorations that interfere with mail handling.

Sources were checked on September 11, 2026. This article uses USPS physical standards, publisher facts, and editorial interpretation. It is not a hands-on mail test of any postcard book.

What USPS standards should colorists care about?

USPS Domestic Mail Manual 201 lists physical standards for cards, including minimum and maximum dimensions, thickness, rectangular shape, aspect ratio, address-side requirements, and attachment rules. It also says a card must be of uniform thickness and made of unfolded, uncreased paper or cardstock that permits legible address and marking information.

For a coloring postcard user, the practical translation is simple:

  • Keep the card flat.
  • Keep the address side readable.
  • Avoid bulky or loose additions.
  • Do not cover the postage or delivery address area with art.
  • Do not assume every decorated card qualifies for the same postage treatment.
  • Check current postal guidance before sending anything important.

Are Johanna Basford coloring postcards meant to be sent?

Publisher titles and descriptions support the postcard use case. Penguin Random House International Sales lists Lost Ocean: 36 Postcards to Color and Send and says the cards are for coloring and sending or keeping. It also lists Magical Jungle: 36 Postcards to Color and Send. Orion lists Secret Garden: 20 Postcards as detachable postcards and says to decorate the cards and share them.

That supports the general intended use. It does not prove that every finished card will mail cleanly after heavy marker, gel pen, stickers, water media, or dimensional embellishments.

What coloring supplies are safest for mail?

Colored pencils are the safest starting point because they add color without much moisture or thickness. They are also easier to control near the address side and edges.

Gel pens can work, but let them dry completely. Raised or glossy dots may smear, transfer, or catch more easily than pencil layers. Keep gel accents on the art side when possible.

Water-based markers and alcohol markers are riskier. They may soak through, show on the address side, feather, or leave the card curled. A marker-colored card might still be mailable, but test first and avoid mailing a card whose address side is stained or hard to read.

Paint, glue, glitter, rhinestones, foam stickers, waxy buildup, and thick collage pieces are poor choices for a postcard you want to send without an envelope.

Should you use an envelope?

Use an envelope when the card matters. An envelope is the practical choice when:

  • The card is going to someone important.
  • You used gel pen, marker, watercolor pencil, or paint.
  • The card has a curled edge.
  • The address side has show-through.
  • You added stickers or any raised detail.
  • You are unsure about postage or dimensions.

Mailing a colored card as a postcard is charming, but preserving the finished art may matter more than the postcard-rate idea.

How should you prepare the address side?

Keep the address side boring. That is good. A readable address side helps the finished art get where it is going.

Before mailing, check:

  1. The delivery address is dark and easy to read.
  2. The return address is present if you want the card returned if undeliverable.
  3. The postage area is clear.
  4. No color or gel pen makes the address hard to scan.
  5. The card is flat, dry, and not sticky.
  6. Nothing loose can detach during processing.

If you want to write a long message, use an envelope instead of crowding the address side.

Can you mail cards colored with alcohol markers?

Maybe, but colored pencils are safer. Alcohol markers often soak through paper, and postcard stock varies. If the marker bleeds to the address side, the card may become hard to read or less attractive to send.

If you still want to try alcohol markers, test a low-stakes card from the same set. Put scrap paper underneath while coloring. Let the card dry fully. Then check the address side in daylight before writing the address.

Can you mail cards with stickers or washi tape?

Use caution. USPS standards discuss acceptable and unacceptable attachments for cards, and attachments should not interfere with processing. Flat paper labels can be different from thick, raised, loose, glossy, or edge-lifting decorations.

For a postcard you truly want delivered, skip bulky decoration. For a decorated keepsake, use an envelope.

What about postcard size?

Some coloring postcard books list dimensions slightly larger than the traditional small postcard mental model. For example, Penguin Random House International Sales lists Lost Ocean postcards at 4.38 x 6.06 inches and Magical Jungle postcards at 4.3 x 6.1 inches. USPS standards include dimension rules for cards and postcards, and rates or handling can vary by size and preparation.

The safest advice is to check current USPS rules or ask at the post office before mailing a finished card without an envelope, especially if the card is larger, thicker, curled, embellished, or important.

Bottom line

You can often mail coloring postcards after coloring them, but mailability depends on the finished card, not only the product title. Use colored pencils, keep the address side clean, avoid bulky decoration, let ink dry, and use an envelope when the card matters.

Sources

  • USPS Domestic Mail Manual 201, Physical Standards for Cards, checked September 11, 2026: pe.usps.com
  • Penguin Random House International Sales, "Lost Ocean: 36 Postcards to Color and Send," checked September 11, 2026: prhinternationalsales.com
  • Penguin Random House International Sales, "Magical Jungle: 36 Postcards to Color and Send," checked September 11, 2026: prhinternationalsales.com
  • Orion, "Secret Garden: 20 Postcards," checked September 11, 2026: orionbooks.co.uk
  • Coloring Book Hub prior article archive, checked September 11, 2026: content/articles/

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