diff --git a/deploy.py b/deploy.py
index c0aab20f42..332c2efce0 100755
--- a/deploy.py
+++ b/deploy.py
@@ -33,6 +33,11 @@
 HELM_RELEASE_NAME = "preview"
 HELM_CHART_DIR = ROOT_DIR / "kubernetes" / "loculus"
 
+# By default, uses K3s v1.31: https://hub.docker.com/r/rancher/k3s/tags?name=v1.31
+# K3s v1.31 is the latest version which installs Traefik v2 (Traefik v3 is not yet supported by Loculus)
+# Also see: https://docs.k3s.io/upgrades#version-specific-caveats
+DEFAULT_K3S_IMAGE = "rancher/k3s:v1.31.14-k3s1"
+
 WEBSITE_PORT_MAPPING = "-p 127.0.0.1:3000:30081@agent:0"
 BACKEND_PORT_MAPPING = "-p 127.0.0.1:8079:30082@agent:0"
 LAPIS_PORT_MAPPING = "-p 127.0.0.1:8080:80@loadbalancer"
@@ -68,6 +73,11 @@
 )
 cluster_parser.add_argument("--delete", action="store_true", help="Delete the cluster")
 cluster_parser.add_argument("--bind-all", action="store_true", help="Bind to all interfaces")
+cluster_parser.add_argument(
+    "--k3s-image",
+    default=DEFAULT_K3S_IMAGE,
+    help="Specify the k3s image to use for the cluster (default: %(default)s)",
+)
 
 helm_parser = subparsers.add_parser("helm", help="Install the Helm chart to the k3d cluster")
 helm_parser.add_argument(
@@ -180,10 +190,13 @@ def handle_cluster():
     if cluster_exists(CLUSTER_NAME):
         print(f"Cluster '{CLUSTER_NAME}' already exists.")
     else:
-        run_command(
-            f"k3d cluster create {CLUSTER_NAME} {' '.join(port_bindings)} --agents 1",
-            shell=True,
-        )
+        command = f"k3d cluster create {CLUSTER_NAME} {' '.join(port_bindings)} --agents 1"
+
+        if args.k3s_image:
+            command += f" --image {args.k3s_image}"
+
+        run_command([command], shell=True)
+
     install_secret_generator()
     while not is_traefik_running():
         print("Waiting for Traefik to start...")
@@ -413,8 +426,8 @@ def generate_configs(from_live, live_host, enable_ena, values_files=None):
         [
             "python",
             "kubernetes/config-processor/config-processor.py",
-            temp_dir_path,
-            output_dir,
+            str(temp_dir_path),
+            str(output_dir),
         ]
     )
     print(f"Config generation succeeded, processed config files available in {output_dir}")