Southwest Checked Baggage Liquid Rules 2025: What You Can and Can’t Pack?

Packing for a flight often gets confusing, especially when it comes to liquids. Many travelers worry about what they can or cannot carry in their bags. With Southwest Airlines, the rules for checked baggage are more relaxed compared to carry-ons, but there are still some important restrictions you should know. 

You can pack full-size toiletries and most personal care items, but certain hazardous or flammable liquids are completely banned. This blog will guide you through everything you need to know about Southwest checked baggage liquid rules, from what’s allowed to what’s not, along with smart packing tips to make your journey smooth and stress-free.

Southwest’s Checked Baggage Policy

Before you start packing liquids, it’s important to know how Southwest’s checked baggage policy works. The airline is well-known for being traveler-friendly and is one of the few major U.S. carriers that allows two checked bags free of cost.

Each checked bag can weigh up to 50 pounds (23 kg) and measure 62 inches (length + width + height). However, even with this flexibility, Southwest must follow the Transportation Security Administration (TSA) safety guidelines that restrict certain materials. Liquids are allowed in checked luggage, but hazardous or flammable ones are strictly prohibited.

Key points to remember:

• Southwest allows two free checked bags per passenger.

• Bags over 50 lbs or larger than 62 inches may incur extra charges.

• Liquids can be packed in checked bags, but they must comply with TSA’s safety standards.

• TSA officers can open your bag if there’s suspicion of leakage or restricted content.

Following these basic guidelines ensures your bag passes inspection easily and avoids delays during check-in.

Allowed Liquids in Southwest Checked Baggage

The good news is that Southwest Airlines doesn’t apply the same strict liquid limits for checked baggage as for carry-ons. You can pack full-size bottles and containers as long as they are properly sealed and not hazardous.

Here’s what you can safely include:

• Full-size toiletries: You can pack large bottles of shampoo, conditioner, lotions, toothpaste, and sunscreen.

• Non-flammable liquids: Products like mouthwash or gel-based items that don’t contain alcohol or chemicals are permitted.

• Medication: You can pack liquid medicines in checked bags, but if it’s something critical, always keep it in your carry-on for quick access.

• Baby items: Baby lotion, oil, and formula are all allowed in checked baggage when packed securely.

Although full-size toiletries are allowed, always ensure they’re tightly sealed. A small leak can damage clothes or other items in your bag.

Prohibited Liquids in Southwest Checked Baggage

Even though Southwest allows personal liquids, there are strict safety restrictions on hazardous substances. The airline does not allow anything that can catch fire, corrode, or react chemically.

Liquids you cannot pack:

• Household chemicals: Items such as bleach, floor cleaners, or liquid detergents are not allowed.

• Highly flammable liquids: This includes paint, fuel, kerosene, or lighter fluid.

• Flammable aerosols: Pressurised spray cans like hair sprays or insecticides that are labeled as “flammable” are prohibited.

• Corrosive liquids: Substances like acids, peroxides, or products that can cause chemical reactions must never be packed.

If TSA identifies these in your checked bag, the items will be removed, and your bag may be delayed or rejected. Always double-check the label on products before packing them.

How to Secure Liquids Properly in Checked Baggage?

Even permitted liquids can cause trouble if they spill or leak inside your suitcase. Proper packing ensures both safety and convenience.

Here are a few smart ways to secure liquids:

• Use zip-lock bags: Place all bottles and containers inside clear plastic bags to prevent leaks.

• Seal bottle caps: Wrap tape around bottle caps or lids to keep them from opening under pressure.

• Pack liquids in the center: Keep bottles surrounded by clothes for cushioning during handling.

• Leave some space: Avoid filling containers to prevent bursting due to cabin pressure.

• Avoid glass bottles: If possible, use travel-friendly plastic containers instead of glass to reduce breakage risk.

Taking these steps not only protects your belongings but also reduces the chance of your bag being flagged during screening.

Flying with Liquids: Checked vs Carry-On

Many travelers often get confused about where to pack their liquids,  in checked baggage or carry-on. The choice depends on the type of liquid and how essential it is during your flight.

Here’s how to decide smartly:

• Carry-on liquids: The TSA 3-1-1 rule applies; containers must be under 3.4 ounces (100 ml) and fit inside one quart-sized clear bag. This rule is stricter for items like gels, lotions, and sprays.

• Checked liquids: You can pack full-size bottles such as shampoo, lotion, and mouthwash without restrictions on size or quantity, as long as they are non-hazardous.

• Critical items: Always carry essential medications, inhalers, or medical liquids in your hand luggage for quick access.

• Connecting flights: If you’re switching planes, especially through different airports, be mindful that the next airline may have its own set of baggage rules.

By planning your packing strategy based on necessity and airline guidelines, you can save both time and stress at security checkpoints.

Important Tips Before You Fly with Southwest

Packing liquids safely is more than following rules; it’s about being careful, organised, and aware of what can go wrong during transit. Here are a few helpful reminders to make your travel experience smoother.

Smart tips for travelers:

• Check your carry-on before check-in: Remove vital items such as IDs, medication, and documents before your bag goes into the hold.

• Label your containers: If you’re carrying homemade liquids or refilled bottles, label them to help TSA officers identify their contents.

• Plan your packing early: Don’t rush the night before. Organising early ensures you don’t mix restricted and permitted items.

• Use protective pouches: Leak-proof pouches or double-layered plastic bags help contain accidental spills.

• Review the airline’s latest policy: Southwest occasionally updates its baggage terms. Reviewing them online before your trip can save you from surprises.

These simple habits help prevent mishaps and ensure your belongings reach your destination safely.

Booking Flights and Packing Smart with Affluence Travels 

When you book your flight with Affluence Travels, you don’t just get competitive fares; you also gain access to essential travel insights like baggage rules, packing tips, and flight updates in one place.

Why choose Affluence Travels  for your Southwest flights:

• Compare airfares: View real-time flight prices for Southwest and other major airlines to find the best deals.

• Get baggage information: Learn about checked baggage limits and what’s allowed before booking.

• Receive instant updates: Stay informed about flight delays, policy changes, or terminal updates directly via email or text.

• Enjoy quick bookings: Secure your flight in just a few clicks with a smooth, transparent process.

With Affluence Travels, you can confidently pack your bags knowing all airline guidelines are clear before you board.

Conclusion

Southwest's checked baggage liquid rules make packing simpler and travel stress-free. You can bring full-size toiletries and non-flammable liquids, but stay away from hazardous or restricted items like bleach or lighter fluid. Always seal containers well and follow TSA’s guidelines for a smooth check-in experience.

If you’re ready to plan your next trip, book your Southwest flight with Affluence Travels. Enjoy clear baggage details, real-time flight updates, and a seamless booking experience, all designed to make your journey comfortable and worry-free.