How Small of a Hole Can an Opossum Fit Through?

If you’ve ever wondered how a chunky, slow-moving opossum ended up in your attic, the answer lies in their shockingly sneaky superpower: squeezing through holes the size of a soda can. Yep, these marsupials don’t need a gaping hole or wide-open door, they just need about 3 to 4 inches of space, and they’re in.

At AAAC Wildlife Removal, we’ve seen full-grown possums slip through gaps homeowners didn’t even think twice about. This isn’t just fun trivia, it’s critical info if you want to keep your home critter-free. Let’s dig into just how small of a space an opossum can use to wiggle their way into your property, and what you can do about it.

Why Entry Size Matters?

Most homeowners don’t inspect their crawl space with a tape measure in hand, but when it comes to opossums, they probably should. Knowing the exact size of a gap that allows entry isn’t just useful, it’s the difference between a calm night’s sleep and hearing scratching noises behind your walls at 2 a.m.

Opossums aren’t trying to be pests. They’re just following the scent of food, shelter, or warmth, and if your home offers a hole even a few inches wide, they’ll treat it like an open invitation. AAAC Wildlife Removal professionals regularly seal up these pint-sized access points because they know one thing: if you miss a gap, an opossum won’t.

The Flexible Anatomy That Makes It Possible

Opossums might look bulky, but their bodies are built for tight spaces. Their skeletal structure includes a small, narrow skull and a flexible spine, allowing them to flatten and twist through tight openings that would stop larger-boned animals in their tracks.

Unlike animals with rigid ribcages, opossums have cartilage-rich chests that compress easily, making them surprisingly squishy. Their low body weight relative to size also gives them the advantage of fitting through holes that seem impossible, until you see it happen. This is why sealing anything under 4 inches wide is no joke when you’re trying to keep them out.

Just How Small of a Hole Can They Fit Through?

Here’s the jaw-dropper: most adult opossums can squeeze through holes as small as 3 to 4 inches in diameter. That’s roughly the size of a tennis ball or a soup can opening, way smaller than most people expect for an animal that can weigh up to 14 pounds.

We’ve seen it firsthand at AAAC Wildlife Removal. Clients are often shocked when we point to a seemingly harmless gap under a porch or in a soffit vent that turns out to be a possum expressway. If you can fit a closed fist through it, chances are, a determined opossum can too.

Sneaky Entry Points Around Your Home

Most homeowners aren’t thinking about 3-inch gaps when checking their house for invaders, but opossums are. These marsupials are opportunistic and surprisingly good at finding the weakest links in a structure.

Many of the most overlooked spots around a home can be just wide enough to let one in, especially if it’s hidden, dark, or rarely inspected. Here are the most common entry points our technicians find during property inspections:

• Crawl Space Vents: Often loosely screened or partially rusted, these vents typically have gaps at the corners that exceed 3 inches.
• Deck Skirting or Lattice Gaps: Decorative wood or plastic barriers around decks can warp or shift over time, leaving open spots.
• Attic Gables and Roofline Vents: These higher-up points are often covered with mesh that deteriorates, tears, or detaches.
• Loose Siding or Fascia Boards: Missing or damaged panels create narrow but accessible gaps that lead straight into walls or attics.
• Pet Doors Left Open Overnight: Even smaller pet doors designed for cats can accommodate an adult opossum.
• Soffits and Eaves: Aging or chewed soffit panels often have just enough give to allow entry if they’re not sealed tight.
• Damaged Screens or Window Wells: Openings around basement windows or screened porches offer easy shelter if they’re not reinforced.
• Gaps in Roof Tiles or Shingles: Especially near flashing or chimney bases, small shifts in material can create the perfect entry slot.
• Mobile Home Skirting: Gaps under mobile homes often go unnoticed and provide ideal shelter for nesting opossums.

If any of these look questionable, or if you can fit a soda can through the gap, it’s likely time to get it sealed. Prevention is always cheaper than cleanup.

Pro Tips for Blocking Those Gaps

You don’t need to turn your house into Fort Knox, but you do need to seal off any opening 3 inches or wider. Start by inspecting your foundation, vents, and roofing edges, especially areas where utility lines, AC hoses, or plumbing pipes enter the home. Even a slight gap or warped siding can become an entry point if left unattended.

When sealing these gaps, materials matter. Temporary fixes like duct tape or chicken wire won’t cut it against an opossum’s claws and determination. You’ll want to go in with permanent solutions designed to handle pressure, gnawing, and weather exposure. Here’s what we recommend:

• Use ¼-inch hardware cloth: It’s rigid enough to hold its shape and small enough to block an opossum’s snout.
• Install galvanized steel mesh over vents and crawlspace entries: Durable, rust-resistant, and nearly impossible to chew through.
• Apply caulking foam around pipe openings: Expanding foam fills tight gaps, then hardens to block airflow and scent trails.
• Add flashing or kickplates along weak boards and siding: These smooth metal barriers make it harder for opossums to grip and pry.
• Avoid chicken wire: It bends easily and creates gaps when pressed, making it basically useless against wildlife.
• Test with the “soda can rule”: If a standard 12 oz can fits through a gap, assume a possum can too, and seal it.

These fixes aren’t overkill, they’re exactly what we use at AAAC Wildlife Removal on homes across the region.

Real Fixes From the Field: What AAAC Wildlife Removal Sees

We once handled a case where an opossum was sneaking into a garage through a 3.25-inch gap behind a utility box, barely visible from the driveway. After sealing it with custom-cut steel mesh and weatherproof foam, the problem vanished overnight.

Another client had a deck skirt with warped lattice just under four inches wide. The possums were bedding down under there like it was a free Airbnb. We replaced it with reinforced barrier panels and added gravel trenches, zero returns since. These real-world examples show that precision matters when it comes to opossum-proofing.

Opossums Are Crafty, But You’re Smarter

At the end of the day, opossums aren’t masterminds, they’re just great at taking advantage of what’s already there. A few inches of space might not seem like a big deal, until it becomes the gateway to attic parties and porch chaos.

With a little awareness, the right materials, and help from AAAC Wildlife Removal, you can turn your home into a no-entry zone. Don’t let a tiny gap turn into a major headache, we’ll help you shut it down before they move in.

Final Take: Tiny Gaps, Big Problem

A 3-inch opening is more than enough for an adult opossum to squeeze into your home, and we’re not talking hypotheticals. From roofline vents to deck skirting, these entry points are everywhere, and most homeowners never realize it until the scratching starts.

Once inside, they’ll find dark, undisturbed spots to nest, often damaging insulation, ductwork, or wiring along the way. Ignoring small gaps gives these opportunists exactly what they need to settle in and create bigger problems fast.

AAAC Wildlife Removal specializes in identifying those hard-to-spot access points. We don’t just trap; we secure, seal, and prevent reentry with proven exclusion techniques that work long-term. If you want the job done right, we’re the team to call.

Let AAAC Wildlife Removal Seal the Deal!

Think a tiny gap isn’t a big deal? Opossums would love for you to keep thinking that. If you’ve spotted signs of entry, or just want peace of mind, AAAC Wildlife Removal is ready to inspect, seal, and secure every inch of your property.

We’re pros at finding entry points you didn’t even know existed. Call us today for a thorough inspection and let’s shut the door on those sneaky marsupials for good.