About Us


It's the On the Rocks mission to help climbers of all ages, skill levels, and abilities learn how to safely and confidently enjoy all styles of rock climbing, while having an awesome time. Leslie Timms, Owner and Head Guide, is a fully accredited PCGI Lead Guide and approved PCGI Mentor, as well as an accomplished professional rock climber. On the Rocks is a team of passionate rock climbers and certified guides, keen to share years of experience with those keen to learn.

Safety is always our #1 priority and that is why On the Rocks strictly hires Certified Guides, teaching the most current and efficient rock climbing techniques available.

Good times guaranteed On the Rocks! 


  We are based out of Thornbury, Ontario (where On the Rocks was born), and our team of certified Single Pitch Guides offer guided adventures and courses at Rattlesnake Point and the Beaver Valley crags (Metcalfe Rock, The Swamp, etc).

We are open from May 1st through October, but we can squeak in some earlier/latertrips and courses if weather permits. 

Please do not hesitate to inquire about custom locations/courses!

Leslie Timms

Owner/Head Guide 

Certified PCGI Lead Guide 
Approved PCGI SPG Course Provider/Examiner
PCGI Multi-Pitch Guide Course 
Wilderness First Responder

Algonquin Outdoor Adventure Program Graduate
Climbing Athlete: Arc'teryxLa SportivaSterling Rope


Outdoor Climbing Accomplishments:

Redpointed sport routes up to 5.13d

Onsighted sport routes up to 5.13a

Redpointed traditional routes up to 5.13b

Onsighted traditional routes up to 5.12a

Bouldered up to V10

First Ascents: Above the Clouds 5.13b (mixed), Stratus Fear 5.12d (trad), Arrested Development 5.13a (sport), Ripple Effect 5.12c (sport), Whoopee Cushion 5.12c (sport), Fortune Teller 5.12c, Stihl Your Face 5.12 (sport), Weekday Warrior 5.11a (sport), Decade 5.11a (sport).



Leslie has been an aspiring guide and adventurer for most of her life. Her passion for epic adventures started with a love for canoe tripping after months of summer outdoor education training in high school. She was then accepted into the Outdoor Adventure Program at Algonquin College, one of the top outdoor education programs in Canada.

During her years at college she discovered rock climbing and after graduating at the top of her class, Leslie hit the road to begin her career as a climber. Leslie has since climbed difficult boulders, sport routes and traditional cracks all over the world. She has developed new routes on the Niagara Escarpment, and given back through countless hours of climbing access, education, community initiatives.


After falling in love with the Beaver Valley on a climbing trip after college, Leslie moved to Thornbury, Ontario to be close to the rocks. She has since established and climbed several difficult traditional and sport routes in Ontario, including the First Ascent of Above the Clouds 5.13 trad/mix at Lions Head.


Leslie is a certified PCGI Lead Guide with Professional Climbing Guide Institute and also an approved PCGI Mentor, approved to certify other PCGI Guides across Canada and the US. She has guided and taught rock clinics all over North America, and at festivals like the Arc'teryx Climbing Academy in Squamish and Red Rock Rendezvous in Las Vegas. On the Rocks is Leslie's vision of collaborating with other passionate certified guides to provide the absolute best climbing courses and experiences on the Niagara Escarpment. 

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Climbing Guide


Certified PCGI Single Pitch Guide  

When I was a young lad, I was lucky enough to go rock climbing on a school trip. This chance encounter sparked a life long passion, and changed my life for the better. Since then I have used climbing to be the facet for my personal development. It has taken me around the world, to the tops of mountains, and embedded me in the hearts of cultures different than my own. In the climbing community I have found lifelong friendships. The lessons taught to me through climbing are carried with me always. Fear of heights, fear of falling, fear of failure. Overcoming and succeeding in spite of these fears is what climbing, and life, is all about. 
Now I get fulfillment from taking new climbers out. On the very same rocks where I began my journey, I get to introduce others to an activity that has given me so much. My job is to make the day as safe as possible, and to enable you to rise above fear, rise above doubt, and surprise yourself with what you're really capable of.




Climbing Guide

Certified PCGI Single Pitch Guide

Wilderness First Aid

I've spent most of my life growing up here in southern Ontario. I love it here, the lakes, the forests, the trails, and the rocks. My parents brought me up in a lifestyle that laid emphasis on being a part of these things. Naturally, the best way to be a part of the limestone was to get on it. I'll never forget my first time out on the rock: I think I was about 7 when my dad shouted to climb. The feeling was incredible.  The thought that only what my hands and feet could reach is what mattered at this moment, and like that I was hooked on the bubble that created itself around me. Though I've been climbing for some time now, I try to never lose sight of that feeling. To watch that excitement crawl it's way down the arms of new climbers as they reach up is what drives me. Climbing has been such a positive aspect of my life and it is such a privilege to be able to share it with others. Look forward to tying in with you.





Climbing Guide 


Certified PCGI Single Pitch Guide

Wilderness First Responder

Since a young age I have always had the passion for going up. When I was 8 the local fire department found themselves at my house because I had climbed a tree and the neighbours were scared for me. 


Through the Canadian Cadet Program I was introduced to rock climbing and during college I was able to meet other climbers and start my journey. Climbing has always been the stable part of my life and the one thing I can look to when things get tough. Along the way I have tried to become a well rounded climber participating in all styles, but when asked I call myself a trad climber. I feel most alive on the rock with gear and a rope and no path that you have to follow. The exploration side of trad climbing cannot be found anywhere else in the climbing world and for me makes all of the stresses of life go away for those moments I get to spend on the wall. Since 2014 I have been working as a full-time rock climbing guide at Metcalfe. I enjoy seeing the spark in eyes when someone discovers climbing for the first time or when their mind is blown learning a new technical system. I hope that one day we can share the ends of a rope together or I get to see you fall in love with climbing.




Climbing Guide 


Certified PCGI Single Pitch Guide

Wilderness First Aid

Adam was raised with a passion to pursue outdoor adventures. Beginning with family camping trips, cadet excursions and finally an  invitation to climb when he was 14 with his cousin. Having spent many days at the local gym, Adam soon realized the climbing community is where he needed to be. While working at the gym, it sparked an interest in Adam to teach others about climbing and share his passion. He discovered the local crags around Milton in which his passion for climbing and his love of the outdoors collided. It’s the time and energy others have invested in him that has inspired Adam to share his expertise, and mentor others in the technical aspect of climbing, as well as making a positive impact in the climbing community. When winter ends, the ice has melted, and ice tools are hung for storage, Adam can be found hanging around any one of the local Milton crags with friends. 




Climbing Guide

Certified PCGI Single Pitch Guide

Wilderness First Responder


I started rock climbing more than 12 years ago on the Niagara Escarpment, and since that time I've travelled to climb every year, visiting many areas in North America, as well as Japan and recently Europe. My favourite climbing area is Red Rock Canyon outside Las Vegas, for the scenic beauty and variety. While I started climbing using traditional protection and climbing mostly cracks, I love all the different types of climbing, from bouldering to sport to multi-pitch trad, and even ice climbing and alpinism. The focus and excitement in climbing is something special, and something I love to share. It makes me happy to see someone I've introduced to the sport or taught achieve their goals and get excited to climb! I look forward to getting out and climbing with you!



Climbing Guide

Certified PCGI Top Rope Guide
PCGI Rescue Course 
Registered Nurse

Hi I'm Pam! I'm 1/2 Philippino and I still need sunblock. What can I say!? I climb sport, trad, multi-pitch, and really enjoy mountaineering and alpine climbing with crampons and ice axe. I love it so much that I live in both Collingwood ON and Golden, BC. I know what it's like to climb in a new area, to transition onto new rock. My goal is to provide you with a safe and fun learning experience on the spectacular Niagara Escarpment!






705 888 8723 (TRAD)




7 Days a week

April 15 - October 15

218 Alice St. W

Thornbury ON

N0H 2P0