Old Tunnel State Park: Guide to Bat Viewing, History & Hiking
Old Tunnel State Park stands as Texas’s smallest state park at just 16.1 acres, yet it hosts one of the most spectacular wildlife spectacles in North America. From May through October, approximately 3 million Mexican free-tailed bats emerge from a historic railroad tunnel each evening, creating a swirling “bat tornado” visible from two dedicated viewing areas.
Located 11 miles south of Fredericksburg in the Texas Hill Country, this former railway tunnel maintains the perfect thermal environment for migrating bat colonies. The park offers free day-use access and ticketed evening bat viewing programs that draw wildlife enthusiasts from across the globe.
According to the Texas Parks and Wildlife Department, the colony consumes up to 30,000 pounds of insects nightly, providing an estimated $12 million in annual agricultural pest control value to local farmers. This remarkable ecological service makes the park a vital conservation site within the Texas Hill Country.
Visitors planning a broader Hill Country adventure should also explore Guadalupe River State Park for additional outdoor activities within a short drive.
Old Tunnel State Park Quick Facts for 2026
| Feature | Details |
|---|---|
| Location | 10619 Old San Antonio Road, Fredericksburg, TX 78624 |
| Park Size | 16.1 Acres (Smallest Texas State Park) |
| Bat Population | ~3 Million Mexican Free-tailed Bats |
| Viewing Season | May 1 – October 31 |
| Peak Months | August – September |
| Day Use Hours | Sunrise to 5:00 PM Daily |
| Entrance Fee | Free (Day Use Only) |
| Bat Viewing Tickets | Required for after-hours entry |
| Contact | (866) 978-2287 |
| GPS Coordinates | 30.1572° N, 98.8456° W |
How to Get to Old Tunnel State Park
The park sits along Old San Antonio Road (FM 1376), approximately 11 miles south of Fredericksburg and 15 miles north of Comfort. The entrance is clearly marked with Texas State Parks signage on the west side of the highway.
Driving Directions from Major Cities
- From Austin (80 miles): Take US-290 West to Fredericksburg, then follow FM 1376 South for 11 miles. Total drive time: approximately 1.5 hours.
- From San Antonio (70 miles): Take I-10 West to Comfort, then follow FM 1376 North for 15 miles. Total drive time: approximately 1 hour 15 minutes.
- From Houston (200 miles): Take I-10 West to San Antonio, then follow directions above. Total drive time: approximately 3.5 hours.
- From Dallas (250 miles): Take I-35 South to Austin, then US-290 West to Fredericksburg. Total drive time: approximately 4 hours.
Parking Information
The main parking area accommodates approximately 50 vehicles and fills quickly during peak bat viewing season. An overflow parking lot opens when the main lot reaches capacity, located a short walk from the viewing areas.
ADA-accessible parking spaces are available near both viewing areas. Visitors requiring accessible parking should arrive early, as these limited spaces are allocated on a first-come basis.
2026 Bat Viewing Tickets: Prices, Areas, and Reservations
All visitors remaining in the park after 5:00 PM during bat season must possess a valid ticket. The park uses an online-only reservation system with no on-site ticket sales.
Upper Viewing Area vs Lower Viewing Area
| Viewing Area | Days | Price | Capacity | Age Restriction |
|---|---|---|---|---|
| Upper Deck | Nightly (May-Oct) | Free | 100 visitors | All ages welcome |
| Lower Deck | Thursday-Sunday | $5 per person | 70 visitors | Ages 4 and up |
The Upper Viewing Area sits on a hillside overlooking the tunnel exit, providing panoramic views of the bats dispersing across the landscape. This area is ideal for families with young children and those seeking a more relaxed experience.
The Lower Viewing Area offers a closer, more intimate experience near the tunnel entrance. A ranger-led educational program precedes the emergence, providing detailed insights into bat biology and conservation.
How to Reserve Bat Viewing Tickets
- Visit the Texas State Parks reservation website or call (512) 389-8900.
- Select “Old Tunnel State Park” and choose your preferred date.
- Choose Upper or Lower Viewing Area based on availability.
- Complete payment for Lower Deck tickets ($5 per person).
- Print or save your confirmation email for park entry.
Tickets become available 60 days in advance and sell out quickly for weekend dates in August and September. The park recommends booking at least 2-3 weeks ahead during peak season.
Best Time to Visit Old Tunnel State Park
Seasonal Viewing Guide
| Month | Bat Activity | Emergence Quality | Crowd Level |
|---|---|---|---|
| May | Colony arriving | Moderate | Low |
| June | Population growing | Good | Low-Medium |
| July | Peak population | Very Good | Medium |
| August | Maximum activity | Excellent | High |
| September | Peak viewing | Excellent | High |
| October | Migration begins | Good | Medium |
August and September deliver the most dramatic emergences, with up to 3 million bats forming a visible “bat tornado” as they spiral upward from the tunnel. The colony reaches maximum size, and emergence times become more predictable.
May and June offer quieter experiences with smaller crowds. The colony is still establishing, but visitors enjoy a more intimate atmosphere and easier ticket availability.
October provides a unique end-of-season experience as bats prepare for migration. Emergences remain impressive, and cooling temperatures make waiting more comfortable.
Daily Emergence Timing
Bats typically emerge between 7:00 PM and 9:00 PM, depending on sunset time and weather conditions. The park updates a recorded information line daily at (866) 978-2287 with predicted emergence times.
- Arrive by 6:00 PM for Lower Viewing Area (program begins early)
- Arrive by 7:00 PM for Upper Viewing Area
- Allow 1-2 hours for the complete emergence spectacle
What to Bring for Bat Viewing
Old Tunnel State Park has no concessions, vending machines, or drinking water. Visitors must bring all necessities for a comfortable experience.
Essential Items Checklist
- ✅ Water – At least 1 bottle per person (no water available in park)
- ✅ Insect repellent – Mosquitoes active in summer months
- ✅ Portable chairs or blankets – For comfortable waiting
- ✅ Binoculars – Enhance viewing of distant bat columns
- ✅ Flashlight – For navigating after emergence ends
- ✅ Light jacket – Temperatures drop after sunset
- ✅ Printed or saved tickets – Required for entry
Photography Equipment Recommendations
- Camera: DSLR or mirrorless with manual settings
- Lens: Fast telephoto (70-200mm f/2.8 ideal)
- Flash: External speedlight with 1/32-1/64 power setting
- Tripod: Sturdy model for long exposures
- ISO: Set between 1600-3200 for low-light conditions
Flash photography is permitted in the Upper Viewing Area but may be restricted in the Lower Area during the educational program. Check with rangers before setting up equipment.
A Century of Railroad History: The Fredericksburg and Northern Railway
The 920-foot tunnel at the heart of Old Tunnel State Park was constructed in 1913 by the Fredericksburg and Northern Railway. As documented by the Texas State Historical Association, this engineering marvel was carved through solid limestone by approximately 100 laborers.
The railroad connected isolated Fredericksburg to San Antonio’s major trade hub, overcoming the formidable “Big Hill” obstacle that had previously limited transportation. For nearly three decades, the line transported agricultural products and passengers throughout the Hill Country.
World War II brought significant changes to national transportation priorities. The federal government deemed the line non-essential to the war effort in 1942, leading to its decommissioning. Steel tracks were dismantled and sold for scrap metal to support wartime manufacturing.
The abandoned tunnel provided an ideal microclimate for migrating bats, with consistent temperatures and humidity levels. Nature reclaimed the space, transforming a transportation corridor into one of Texas’s most important wildlife sanctuaries.
Mexican Free-Tailed Bats: Biology and Behavior
The Mexican free-tailed bat (Tadarida brasiliensis) ranks among the most aerodynamically efficient mammals worldwide. These medium-sized hunters reach flight speeds of 60 miles per hour and climb to altitudes exceeding 10,000 feet.
Their long, narrow wings adapt specifically for fast flight in open spaces, enabling them to intercept high-flying insect swarms inaccessible to other predators. This aerial mastery cements their reputation as masters of the night sky.
The Old Tunnel colony consists primarily of bachelor bats and post-maternity females during summer months. Pregnant females return to Texas in spring but typically choose more humid caves for giving birth before joining the tunnel colony.
These bats possess remarkable metabolisms requiring massive insect consumption. A nursing mother bat can eat up to two-thirds of her body weight nightly to support herself and her offspring.
Echolocation: Nature’s Precision Radar
Bats rely on sophisticated echolocation to navigate darkness and pinpoint prey with remarkable precision. By emitting high-frequency sounds and interpreting returning echoes, they detect insects as small as mosquitoes from several yards away.
Biological studies within the park have identified a small population of cave myotis bats residing alongside the larger free-tailed colony. This diversity adds ecological complexity and provides unique research opportunities for wildlife biologists.
Ecological and Agricultural Value
The bat colony at Old Tunnel State Park provides significant economic benefits to surrounding agricultural areas. These natural pest controllers save local farmers an estimated $12 million annually in pesticide costs and crop damage prevention.
The colony consumes approximately 30,000 pounds of insects nightly, targeting pests like cotton bollworm and corn earworm moth. This biological service reduces chemical intervention needs, promoting sustainable agricultural practices throughout the region.
Research from Bat Conservation International indicates bats contribute over $22 billion annually to the U.S. agricultural industry. Protecting habitats like Old Tunnel remains essential for maintaining this economic and ecological service.
Hiking and Nature Trails
The Old Tunnel nature trail provides a short but rewarding hiking experience through rugged Hill Country terrain. Spanning less than half a mile, the trail winds through dense juniper-oak woodlands with several steep sections requiring sturdy footwear.
Interpretive signs at strategic intervals explain unique geology and ecology. These markers detail limestone formations that enabled both railroad construction and the bat colony’s survival.
- Trail length: 0.4 miles round-trip
- Difficulty: Moderate (steep sections)
- Estimated time: 30-45 minutes
- Best time: Morning hours (cooler temperatures)
Visitors should note the primitive trail may be slippery after spring rain events. Staying on designated paths protects sensitive habitats surrounding the tunnel entrance.
For more extensive trail systems, our guide to Pedernales Falls State Park details over 20 miles of hiking and biking opportunities nearby.
Bird Watching at Old Tunnel State Park
Old Tunnel State Park holds official recognition as a site on the Great Texas Coastal Birding Trail. The park’s varied elevation and diverse plant life support over 150 bird species throughout the year.
Notable Bird Species
- Painted Bunting – Multi-colored plumage, frequent in brushy parking area edges
- Golden-cheeked Warbler – Endangered species, nests exclusively in old-growth Central Texas cedar
- Canyon Towhee – Common year-round resident
- Northern Cardinal – Visible throughout the park
- Various raptors – Circle thermal updrafts above the tunnel
Spring and early summer offer the most rewarding birding, as migratory species utilize the park for nesting. The TPWD bird checklist helps enthusiasts document sightings and contribute to citizen science data.
Early morning provides optimal birdwatching conditions, with cool air encouraging activity and fewer crowds. High-quality binoculars are strongly recommended for appreciating avian residents’ intricate details.
Essential Visitor Rules and Regulations
Due to its small size and sensitive bat colony, Old Tunnel State Park enforces stricter regulations than most Texas parks. These rules protect both visitors and the millions of animals inhabiting the tunnel.
Prohibited Activities
- No Pets: Animals prohibited throughout the park, including inside vehicles
- No Smoking or Vaping: All tobacco products and e-cigarettes banned
- No Camping: Overnight stays prohibited (no facilities available)
- No Drones: Aerial devices disturb wildlife and are not permitted
- No Flash Photography in Lower Area: During educational program
Approaching the tunnel entrance or crossing perimeter fences is strictly forbidden. Rangers monitor these areas to ensure bats remain undisturbed during daylight rest and nightly emergence.
Visitors seeking overnight accommodations should explore Texas state parks with camping in the surrounding region.
Accessibility Features
Old Tunnel State Park provides inclusive experiences for visitors of all physical abilities. Both viewing areas meet or exceed ADA accessibility standards for 2026.
- Upper Viewing Area: Designated accessible parking adjacent to hard-packed caliche trail leading to ramp-accessible deck
- Lower Viewing Area: Accessible via specialized route (contact park staff in advance)
- Picnic Areas: Wheelchair-friendly tables on stable concrete pads
- Restrooms: Accessible portable toilet in overflow parking area during bat season
Where to Stay Near Old Tunnel State Park
Since camping is not permitted at Old Tunnel, visitors requiring overnight accommodations have several nearby options.
Hotels in Fredericksburg (11 miles north)
- Historic Main Street bed and breakfasts
- National chain hotels along US-290 corridor
- Boutique wine country lodges
Nearby State Parks with Camping
| Park | Distance | Camping Options |
|---|---|---|
| Enchanted Rock SNA | 25 miles | Tent sites, primitive camping |
| Inks Lake State Park | 35 miles | Tent, RV, cabins |
| Pedernales Falls SP | 40 miles | Tent, RV sites |
The Hill Country Weekend: Nearby Attractions
A visit to Old Tunnel State Park pairs perfectly with other Hill Country destinations for a complete weekend itinerary.
Fredericksburg (11 miles north)
This renowned German heritage town features a historic Main Street lined with boutiques, restaurants, and wine tasting rooms. After bat viewing, visitors can enjoy authentic German cuisine or explore the 290 wine corridor.
Comfort (15 miles south)
This laid-back town offers a thriving antique and artisan scene. Don’t miss the historic Hygieostatic Bat Roost, a century-old tower providing an architectural counterpart to the natural roost at the state park.
For more inspiration, explore our guide to Hill Country date ideas for unique and romantic suggestions.
Frequently Asked Questions
How much does it cost to visit Old Tunnel State Park?
Day use is completely free for all visitors. However, staying for bat viewing after 5:00 PM requires a ticket. Upper Viewing Area tickets are free (reservation required), while Lower Viewing Area tickets cost $5 per person.
What time do the bats emerge?
Bats typically emerge between 7:00 PM and 9:00 PM from May through October. Exact timing shifts daily based on sunset and weather. Call (866) 978-2287 for daily predicted emergence times.
Can I buy tickets at the park entrance?
No. The park does not sell tickets on-site. All reservations must be made online through the Texas State Parks website or by calling the customer service center. Tickets are available up to 60 days in advance.
Is there drinking water or food available?
No concessions, vending machines, or drinking water are available. Visitors must bring all water and snacks. Nearby Fredericksburg and Comfort offer dining and grocery options for pre-park preparation.
Why are children under 4 not allowed in the Lower Viewing Area?
The Lower Viewing Area requires visitors to remain quiet and still during the educational program near the tunnel entrance. For safety and to avoid disturbing bats, this area is restricted to children age 4 and older.
Is Old Tunnel State Park open year-round?
Yes, the park is open daily from sunrise to 5:00 PM year-round for day use. Bat viewing programs operate only from May 1 through October 31, when the colony is present.
Planning Your 2026 Visit
Old Tunnel State Park demonstrates that even the smallest protected areas can deliver world-class wildlife experiences. This 16-acre sanctuary offers an unparalleled look at the “bat tornado” while preserving a unique piece of Texas railroad history.
Book tickets early, arrive with water and essentials, and respect the strict rules that keep this biological wonder thriving. The nightly emergence delivers a wildlife spectacle that ranks among Texas’s most memorable natural experiences.
As you plan your Hill Country journey, consider pairing your visit with Longhorn Cavern State Park to experience the full geological and biological diversity of the region.
