Which Multi-Pen Is Right for Your Carry-On? A Frequent Flyer’s Guide

Why a Multi-Pen Makes Sense for Air Travel

If you’ve ever fumbled through your carry-on looking for a pen to fill out a customs form or jot down a seat number, you know the struggle. A multi-pen—also called a multifunction pen—packs several ink colors and sometimes a mechanical pencil into one slim body. For frequent flyers, that means less clutter and quicker access when you need it most.

I used to think multi-pens were a gimmick. In school, they ran out of ink fast, and the colors were limited. But once I started flying more, I realized they’re actually perfect for travel. You don't write a novel on a plane; you just need a reliable pen for the occasional note or form. And with multiple colors in one barrel, you can highlight, correct, and mark up without carrying a whole pencil case.

What to Look For: Ink, Refills, and Compatibility

The first thing to check is refill availability. Some brands use proprietary refills that are pricey and hard to find abroad. Others stick to industry standards like ISO D1 or the Japanese 3mm system, so you can buy cheap knockoffs at any stationery store. If you're a frequent flyer, you want a pen you can find refills for in any airport shop.

Next, consider the ink type. Oil-based ballpoint dries fast, which is great for lefties. Gel ink (neutral ink) feels smoother but can smudge if you’re not careful. Some multi-pens even include a mechanical pencil, which is handy for crossword puzzles or sketching in your travel journal.

Budget-Friendly Options: Don’t Overlook the Basics

You don’t need to spend a fortune. Many Chinese brands like M&G, Deli, and Kaco make solid multi-pens with standard red, black, blue, and green gel refills. They’re often available in stationery stores and online for under $5. The main downside is the plastic body—some models have loose threading and can unscrew in your pocket. But if you’re on a budget, these are a fine choice.

Miniso and KKV also carry multi-pens made by these same manufacturers, often with cute designs. Just test the twist mechanism before you buy, because quality varies by batch.

LAMY: Design Meets Function

LAMY, now owned by Mitsubishi Pencil (uni), offers multi-pens in several of their iconic series: ST, logo, cp1, and 2000. They use D1-size ballpoint refills (M21) in black, red, blue, and green, plus an orange marker refill (M55). The ST and cp1 have a rotating mechanism—you twist to select the color. The 2000 and logo use a gravity mechanism: you click once, and the ink color you’ve chosen (by orienting a marker) comes out.

That gravity system isn’t ideal for rapid switching, but for occasional use it’s elegant and compact. If you appreciate minimalist design and don’t need many colors, a LAMY is a stylish travel companion.

Pilot Coleto: The Customizable Workhorse

Pilot’s Coleto line is a favorite among travelers because of its modular refill system. You buy a barrel (holds 2 to 5 refills) and then snap in the refills you want—each refill has its own color button, so you can mix and match. The refills come in 0.3mm, 0.4mm, and 0.5mm, with 15 standard colors and over 30 special editions (metallic, pastel, etc.). There’s even a mechanical pencil and a tiny eraser module.

Coleto refills are 9.3cm long (without the button) and use the proprietary Hi-Tec-C ink, which is smooth and reliable. You can also use longer refills if you trim them. For travelers, this means you can customize a pen with just the colors you need—like a blue for writing and a red for corrections—and leave the rest behind.

Pentel: Understated but Reliable

Pentel might not have the flashiest multi-pens, but they have some gems. The i+ series is fully modular: you buy a barrel and then choose from Energel (fast-drying gel), Sliccies (colored gel), or mechanical pencil refills. The refill caps are color-coded, so you know what’s inside. MUJI’s multi-pens are actually rebranded Pentel i+, with a fully transparent barrel that shows the cap color—a nice touch.

Pentel also makes the Multi 8, a unique eight-color mechanical pencil (lead holder) that uses 2.0mm colored leads. It’s perfect for sketching or color-coding in a travel journal, but it’s a niche product. If you need a versatile drawing tool, this is the only multi-pen of its kind.

uni: The Jetstream Standard

uni (Mitsubishi Pencil) is the multi-pen giant. Their Jetstream line uses oil-based ink that writes smoothly and dries fast—ideal for lefties. The Jetstream multi-pens come in 2- or 3-color versions, and the refills (8.8cm) are the most common size for Chinese knockoffs, so you can always find cheap replacements.

uni’s Style Fit system is similar to Coleto: you pick a barrel (3 to 5 slots) and choose from 16 gel ink colors in 0.28, 0.38, or 0.5mm, plus a mechanical pencil. There’s also a single-slot version for testing colors. If you love the Jetstream feel but want more colors, Style Fit is a great option. The Hobonichi Techo planners include a Jetstream multi-pen every year, so you know it’s a trusted tool.

Refill Compatibility: The Secret to Saving Money

Multi-pen refills are where the industry splits. There are two main standards: ISO D1 (2.3mm diameter, 6.7cm long) and Japanese standard (3mm diameter, lengths vary). LAMY uses D1. Pilot Coleto, Pentel Sliccies, and uni Style Fit use the Japanese 3mm system, but each has slight variations in length.

Here’s a quick breakdown:

• D1 refills: 2.3mm, ~6.7cm – used by LAMY and many European brands. You can find generic D1 refills in many colors.
• Coleto: 9.3cm without button – Pilot-specific, but you can trim longer refills.
• Style Fit / Sliccies: 9.8cm – these are interchangeable, and some Pilot Acroball refills fit too.
• Jetstream: 8.8cm – the most common size for Chinese generic refills, so cheap and easy to find.

Zebra’s multi-pens are a mess—they have two different 3mm sizes (NJK and JK) plus D1, and they don’t interchange. Unless you really like the writing feel, skip them.

Final Thoughts: Pick What Fits Your Flying Style

My advice? If you want a gel ink multi-pen with tons of color options, go with Pilot Coleto. If you prefer oil-based ink that dries fast and you want cheap refills, grab a uni Jetstream. And if you’re a design nerd, a LAMY is a classy choice—just remember to stock up on D1 refills before your trip.

Whichever you choose, a multi-pen is a smart addition to your carry-on. It’s one less thing to rummage for, and you’ll always have the right color on hand. Happy travels!