Drop-Bag Packing Guide: What Goes in Each Bag (by Distance and Time of Day)

Pack every drop bag for the runner who will open it, not the one standing at the start line. That runner is hungrier, colder, more tired and less coordinated than you are right now, so each bag gets the same three-layer build: a base kit that never changes (calories, anti-chafe, socks, blister tape, a pit card), a time-of-day layer (daylight refuel, night transition or sunrise reset) and a weather branch you commit to the night before. Everything goes in labeled freezer bags inside a bright, soft-sided bag, and nothing goes in that you would grieve if it never came back. The checklists below cover 50K, 100K and 100-mile races, the labeling system that works at 3 a.m., and the handoff when a crew is in the picture.

Why drop bags fail, and the rule that fixes it

Drop bags fail in three ways. The bag holds the wrong things because it was packed for the whole race rather than for one moment. The right things are in there, but a tired runner cannot find them in the ninety seconds the stop should take. Or the bag never reached the station. The first two are packing problems, and the same rule solves both: one bag, one moment.

Before packing anything, read the race's drop-bag page. It tells you which aid stations accept bags, the size limit (a small duffel or roughly a five-gallon-bucket volume is common), the drop-off deadline (usually packet pickup or a set time before the start) and the return policy. Bags often come back a day or more after the race, and runners who drop out and leave before the sweep sometimes never see theirs again.

Step one: estimate when you will reach each bag station

You cannot choose the time-of-day layer without a rough arrival estimate, and the estimate has to be honest. Use a conservative average pace that includes aid-station time, not your goal pace. A worked example for a 100-miler with a 6 a.m. start:

• Assume 16 minutes per mile average, stops included. That is about 26 hours 40 minutes, a mid-pack mountain hundred.
• Mile 30 arrives around 8 hours in: roughly 2 p.m., the heat of the day.
• Mile 50 arrives around 13 hours 20 minutes in: roughly 7:20 p.m., dusk. This is the night-transition bag.
• Mile 70 arrives around 18 hours 40 minutes in: roughly 12:40 a.m., deep night with the coldest hours still ahead.
• Mile 90 arrives around 24 hours in: roughly 6 a.m., sunrise. This is the sunrise bag.

Run the same arithmetic for a 100K (a 14-hour finish from a 6 a.m. start puts you at mile 50 to 55 around 6 to 7 p.m., which is a night bag in autumn and a daylight bag in June) and for a 50K, which rarely needs a night layer at all. Then add a margin: if a station falls within about ninety minutes of sunset at your estimate, treat it as a night bag. A headlamp you did not need costs nothing. A dark trail with no lamp costs the race, and the first rule of aid-station work is that you leave the station ready for the next segment, not the current one.

The base kit that goes in every bag

Whatever moment the station serves, every bag gets this base kit. Buy multiples so you are not moving one item between bags.

• Calories for the next segment, in the forms you have practiced with: gels, chews, drink-mix scoops pre-measured into small zip bags (one bag per flask refill), and one savory item.
• Anti-chafe balm. A small tin of Squirrel's Nut Butter is the drop-bag standard because it stays spreadable when cold and goes onto damp skin, which is exactly the condition your feet will be in. One per bag; do not rely on the tin you started with.
• One pair of fresh socks. Toe socks like Injinji Trail Midweight earn their price in drop bags specifically, because a sock change is when between-toe hot spots get caught before they become blisters, and toe socks keep those toes separated afterward.
• A small blister kit: pre-cut strips of Leukotape or kinesiology tape, an alcohol wipe, a sterile needle or safety pin, a small tube of petroleum jelly, a few bandages.
• A pit card: an index card listing what is in the bag and what you intend to do at this station. More on this below.
• Wet wipes in a zip bag, a spare zip bag for used or wet items, and a small trash bag.
• Electrolyte capsules or tabs if they are part of your plan, labeled with the dose you decided on in training.

One note on painkillers: many race medical teams ask runners not to take NSAIDs during ultras. Read your race's medical guidance and talk to your own clinician.

Daylight bag: 50K, and the first half of longer races

The daylight bag has one purpose: refuel and reset skin. It is the only bag most 50Ks need, if they allow one at all.

• Two to three hours of fuel. At 60 to 90 grams of carbohydrate per hour that is 120 to 270 grams, which is roughly five to ten gels, or the pre-measured drink-mix bags plus a few chews.
• A flavor change. If you have been on sweet gels since the start, the savory item is what you will actually eat: a tortilla with nut butter, salted potato chips, a small bag of pretzels. Sweet-to-savory rotation is the simplest fix for the flavor fatigue that stops runners eating.
• Sun kit: sunscreen stick, a fresh cap or buff, sunglasses if you started before light.
• Anti-chafe for the big zones. A stick of Body Glide Outdoor is the fast standing-up application for inner thighs, underarms, the sports-bra line and the vest's shoulder straps; the tin balm is what you use on your feet while sitting for the sock change.

Heat branch: add a second buff or an ice bandana to stuff with ice, arm sleeves for the same job, a light-colored shirt and extra sodium in the form you have practiced with. If the forecast is above about 85°F (29°C), the heat branch goes in every daylight bag, not just the noon one.

Night-transition bag: the one to pack first

In a 100-miler this is the most important bag on the course. Pack it first, and pack it as if you will arrive later than planned, because you probably will.

• Primary headlamp, fully charged, and your backup. Many mountain races require two lamps in the mandatory kit; carry two after dark even when they do not. A 45-gram Nitecore NU25 400 UL is a common choice for the always-in-the-vest backup, and it works as a primary on runnable trail, because the weight is a rounding error and it recharges over USB-C from a small power bank at the next station. If your primary uses a swappable battery pack, the spare goes in this bag, charged, with the date on a strip of tape.
• Long-sleeve base layer and light gloves, even for summer races at altitude. Temperatures keep falling until just after sunrise, and the lowest point comes long after the moment you feel fine leaving the station.
• Warm calories: soup, broth or hot chocolate if the aid station serves them, plus your own instant option that only needs hot water.
• Caffeine for the 1 a.m. to 4 a.m. window, in the form you practiced with.
• Fresh socks, the second pair of the race, and the blister kit.
• Beanie or warm buff, and clear or yellow lenses if dust and insects bother you under a headlamp.

Cold or wet branch: a rain shell if it is not already mandatory kit, a heavier merino sock option, spare gloves in a zip bag, hand warmers, a full dry top layer in a dry bag, and a large trash bag that doubles as an emergency poncho or a dry seat.

Sunrise bag: 100-milers only

• Shoe swap, if you carry a second pair. Feet typically swell over 20-plus hours, so the second pair is a half size up or a wider model. Make the change here unless a blister or a broken shoe forces it earlier.
• Third pair of socks, and a final anti-chafe pass on feet and the big zones.
• Sunscreen, sunglasses, a cap.
• Caffeine, and a breakfast item you can stomach: a breakfast burrito from crew, aid-station pancakes, a bagel.
• A fresh shirt. It is a morale item, and a dry back stops the vest from chafing on a sweat-crusted layer.
• The pit card should say what you will do here in three lines, because your ability to plan will be gone.

Finish-line bag

Most races let you leave a finish bag even though it is not a drop bag by rule. Pack warm layers, recovery slides or loose shoes, a towel, a recovery drink, phone charger, cash and your car keys. Keys never go in a bag that travels out on course.

Labeling and packaging

• One freezer bag per category, labeled in marker: FUEL, FEET, LIGHT, LAYERS, SKIN. A tired runner opens the one bag that matters and ignores the rest.
• Outer bag: bright, soft-sided, water-resistant. A cheap dry bag or a lightweight duffel works. Hard coolers are banned at many races because volunteers haul these bags by hand.
• Label the outside on two sides with bib number, last name, the aid-station name and its mileage, on painter's tape or a luggage tag.
• Add a strip of reflective tape or a colored ribbon, because drop bags sit in piles, in the dark, sorted by strangers.
• Tape the pit card inside the lid or on the top freezer bag.
• Assume the bag sits in the rain for twelve hours. Everything inside is in its own zip bag.
• Nothing valuable. Bags ride in open trucks and sit in fields.

The pit card and the crew handoff

The pit card is the single most useful item in the bag. It lists what the bag holds, what you plan to do at this station, and what you must leave carrying. Three lines are enough: EAT (what and how much), FIX (socks, lube, tape), CARRY OUT (lamp, layer, fuel for the next segment). It removes the decision-making from the moment you are least able to decide.

If you have a crew, drop bags are the backup for stations the crew cannot reach and the mirror of the crew bins at stations they can. Give the crew the same pit cards. Their job is hands; the runner's job is to sit, eat and answer three questions: what hurts, what will you eat, what are you carrying out. The routine is covered in detail in the 90-second aid-station stop and the crew guide. The short version:

1. Runner hands over the vest. Crew refills flasks and restocks fuel to the plan, not to what the runner asks for, because the runner always asks for less.
2. Runner sits and changes socks while the crew looks at both feet under a light.
3. Crew hands over the time-of-day layer from the drop bag: lamp, base layer, gloves.
4. Crew reads back what is now in the vest.
5. Runner leaves eating, not waiting to eat.

Mistakes that show up at every race

• The same bag packed five times, with no time-of-day layer.
• New foods that appear only in drop bags. Everything in the bag has been eaten on a long run first.
• One headlamp for the whole night, with no spare battery and no backup.
• Cotton anything in the night bag.
• No pit card, so a tired brain has to plan from scratch.

Pack the night bag first, the sunrise bag second and the daylight bags last, and you will have spent your attention in the order the race spends yours.