diff --git a/utils/docker/Dockerfile.jammy b/utils/docker/Dockerfile.jammy
index 2f689361bd..bc4b833c67 100644
--- a/utils/docker/Dockerfile.jammy
+++ b/utils/docker/Dockerfile.jammy
@@ -4,6 +4,9 @@ ARG DEBIAN_FRONTEND=noninteractive
 ARG TZ=America/Los_Angeles
 ARG DOCKER_IMAGE_NAME_TEMPLATE="mcr.microsoft.com/playwright/dotnet:v%version%-jammy"
 
+ENV LANG=C.UTF-8
+ENV LC_ALL=C.UTF-8
+
 # === INSTALL dependencies ===
 
 RUN apt-get update && \
diff --git a/utils/docker/Dockerfile.noble b/utils/docker/Dockerfile.noble
index ca628b5b42..69b880f6dc 100644
--- a/utils/docker/Dockerfile.noble
+++ b/utils/docker/Dockerfile.noble
@@ -4,6 +4,9 @@ ARG DEBIAN_FRONTEND=noninteractive
 ARG TZ=America/Los_Angeles
 ARG DOCKER_IMAGE_NAME_TEMPLATE="mcr.microsoft.com/playwright/dotnet:v%version%-noble"
 
+ENV LANG=C.UTF-8
+ENV LC_ALL=C.UTF-8
+
 # === INSTALL dependencies ===
 
 RUN apt-get update && \