diff --git a/lighthouse-cl-only.yml b/lighthouse-cl-only.yml
index e192412f..96b7f161 100644
--- a/lighthouse-cl-only.yml
+++ b/lighthouse-cl-only.yml
@@ -37,6 +37,7 @@ services:
       - ARCHIVE_NODE=${ARCHIVE_NODE:-false}
       - IPV6=${IPV6:-false}
       - CL_P2P_PORT=${CL_P2P_PORT:-9000}
+      - NETWORK=${NETWORK}
     ports:
       - ${HOST_IP:-}${CL_P2P_PORT:-9000}:${CL_P2P_PORT:-9000}/tcp
       - ${HOST_IP:-}${CL_P2P_PORT:-9000}:${CL_P2P_PORT:-9000}/udp
@@ -57,8 +58,6 @@ services:
       - 0.0.0.0
       - --http-port
       - ${CL_REST_PORT:-5052}
-      - --network
-      - ${NETWORK}
       - --port
       - ${CL_P2P_PORT:-9000}
       - --target-peers
diff --git a/lighthouse-vc-only.yml b/lighthouse-vc-only.yml
index 86db8431..4bf7c6fb 100644
--- a/lighthouse-vc-only.yml
+++ b/lighthouse-vc-only.yml
@@ -29,6 +29,7 @@ services:
       - VC_EXTRAS=${VC_EXTRAS:-}
       - GRAFFITI=${GRAFFITI:-}
       - DEFAULT_GRAFFITI=${DEFAULT_GRAFFITI:-false}
+      - NETWORK=${NETWORK}
     volumes:
       - lhvalidator-data:/var/lib/lighthouse
       - /etc/localtime:/etc/localtime:ro
@@ -45,8 +46,6 @@ services:
       - /var/lib/lighthouse
       - --beacon-nodes
       - ${CL_NODE:-http://consensus:5052}
-      - --network
-      - ${NETWORK}
       - --debug-level=${LOG_LEVEL}
       - --metrics
       - --metrics-address
diff --git a/lighthouse.yml b/lighthouse.yml
index d3d44748..011d6c6b 100644
--- a/lighthouse.yml
+++ b/lighthouse.yml
@@ -38,6 +38,7 @@ services:
       - ARCHIVE_NODE=${ARCHIVE_NODE:-false}
       - IPV6=${IPV6:-false}
       - CL_P2P_PORT=${CL_P2P_PORT:-9000}
+      - NETWORK=${NETWORK}
     ports:
       - ${HOST_IP:-}${CL_P2P_PORT:-9000}:${CL_P2P_PORT:-9000}/tcp
       - ${HOST_IP:-}${CL_P2P_PORT:-9000}:${CL_P2P_PORT:-9000}/udp
@@ -58,8 +59,6 @@ services:
       - 0.0.0.0
       - --http-port
       - ${CL_REST_PORT:-5052}
-      - --network
-      - ${NETWORK}
       - --listen-address
       - 0.0.0.0
       - --port
@@ -94,6 +93,7 @@ services:
       - VC_EXTRAS=${VC_EXTRAS:-}
       - GRAFFITI=${GRAFFITI:-}
       - DEFAULT_GRAFFITI=${DEFAULT_GRAFFITI:-false}
+      - NETWORK=${NETWORK}
     volumes:
       - lhvalidator-data:/var/lib/lighthouse
       - /etc/localtime:/etc/localtime:ro
@@ -110,8 +110,6 @@ services:
       - /var/lib/lighthouse
       - --beacon-nodes
       - ${CL_NODE:-http://consensus:5052}
-      - --network
-      - ${NETWORK}
       - --debug-level=${LOG_LEVEL}
       - --metrics
       - --metrics-address
diff --git a/lighthouse/Dockerfile.binary b/lighthouse/Dockerfile.binary
index 04d00e33..2868e076 100644
--- a/lighthouse/Dockerfile.binary
+++ b/lighthouse/Dockerfile.binary
@@ -43,7 +43,7 @@ RUN mkdir -p /var/lib/lighthouse/validators && chown ${USER}:${USER} /var/lib/li
 
 RUN set -eux; \
         apt-get update; \
-        DEBIAN_FRONTEND=noninteractive TZ=Etc/UTC apt-get install -y gosu ca-certificates tzdata; \
+        DEBIAN_FRONTEND=noninteractive TZ=Etc/UTC apt-get install -y gosu ca-certificates tzdata git; \
         rm -rf /var/lib/apt/lists/*; \
 # verify that the binary works
         gosu nobody true
diff --git a/lighthouse/Dockerfile.source b/lighthouse/Dockerfile.source
index c223a634..e439f4fe 100644
--- a/lighthouse/Dockerfile.source
+++ b/lighthouse/Dockerfile.source
@@ -36,6 +36,7 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive TZ=Etc/UTC apt-get install
   ca-certificates \
   wget \
   tzdata \
+  git \
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/*
 
diff --git a/lighthouse/docker-entrypoint-vc.sh b/lighthouse/docker-entrypoint-vc.sh
index 36ea622a..e97ae5ca 100755
--- a/lighthouse/docker-entrypoint-vc.sh
+++ b/lighthouse/docker-entrypoint-vc.sh
@@ -6,6 +6,29 @@ if [ "$(id -u)" = '0' ]; then
   exec gosu lhvalidator docker-entrypoint.sh "$@"
 fi
 
+if [[ "${NETWORK}" =~ ^https?:// ]]; then
+  echo "Custom testnet at ${NETWORK}"
+  repo=$(awk -F'/tree/' '{print $1}' <<< "${NETWORK}")
+  branch=$(awk -F'/tree/' '{print $2}' <<< "${NETWORK}" | cut -d'/' -f1)
+  config_dir=$(awk -F'/tree/' '{print $2}' <<< "${NETWORK}" | cut -d'/' -f2-)
+  echo "This appears to be the ${repo} repo, branch ${branch} and config directory ${config_dir}."
+  # For want of something more amazing, let's just fail if git fails to pull this
+  set -e
+  if [ ! -d "/var/lib/lighthouse/validators/testnet/${config_dir}" ]; then
+    mkdir -p /var/lib/lighthouse/validators/testnet
+    cd /var/lib/lighthouse/validators/testnet
+    git init --initial-branch="${branch}"
+    git remote add origin "${repo}"
+    git config core.sparseCheckout true
+    echo "${config_dir}" > .git/info/sparse-checkout
+    git pull origin "${branch}"
+  fi
+  set +e
+  __network="--testnet-dir=/var/lib/lighthouse/validators/testnet/${config_dir}"
+else
+  __network="--network=${NETWORK}"
+fi
+
 # Check whether we should use MEV Boost
 if [ "${MEV_BOOST}" = "true" ]; then
   __mev_boost="--builder-proposals"
@@ -32,9 +55,9 @@ fi
 if [ "${DEFAULT_GRAFFITI}" = "true" ]; then
 # Word splitting is desired for the command line parameters
 # shellcheck disable=SC2086
-  exec "$@" ${__mev_boost} ${__beacon_stats} ${__doppel} ${VC_EXTRAS}
+  exec "$@" ${__network} ${__mev_boost} ${__beacon_stats} ${__doppel} ${VC_EXTRAS}
 else
 # Word splitting is desired for the command line parameters
 # shellcheck disable=SC2086
-  exec "$@" "--graffiti" "${GRAFFITI}" ${__mev_boost} ${__beacon_stats} ${__doppel} ${VC_EXTRAS}
+  exec "$@" ${__network} "--graffiti" "${GRAFFITI}" ${__mev_boost} ${__beacon_stats} ${__doppel} ${VC_EXTRAS}
 fi
diff --git a/lighthouse/docker-entrypoint.sh b/lighthouse/docker-entrypoint.sh
index fd73915a..a8a7ac46 100755
--- a/lighthouse/docker-entrypoint.sh
+++ b/lighthouse/docker-entrypoint.sh
@@ -19,6 +19,31 @@ if [[ -O "/var/lib/lighthouse/ee-secret/jwtsecret" ]]; then
   chmod 666 /var/lib/lighthouse/beacon/ee-secret/jwtsecret
 fi
 
+if [[ "${NETWORK}" =~ ^https?:// ]]; then
+  echo "Custom testnet at ${NETWORK}"
+  repo=$(awk -F'/tree/' '{print $1}' <<< "${NETWORK}")
+  branch=$(awk -F'/tree/' '{print $2}' <<< "${NETWORK}" | cut -d'/' -f1)
+  config_dir=$(awk -F'/tree/' '{print $2}' <<< "${NETWORK}" | cut -d'/' -f2-)
+  echo "This appears to be the ${repo} repo, branch ${branch} and config directory ${config_dir}."
+  # For want of something more amazing, let's just fail if git fails to pull this
+  set -e
+  if [ ! -d "/var/lib/lighthouse/beacon/testnet/${config_dir}" ]; then
+    mkdir -p /var/lib/lighthouse/beacon/testnet
+    cd /var/lib/lighthouse/beacon/testnet
+    git init --initial-branch="${branch}"
+    git remote add origin "${repo}"
+    git config core.sparseCheckout true
+    echo "${config_dir}" > .git/info/sparse-checkout
+    git pull origin "${branch}"
+  fi
+  bootnodes="$(paste -s -d, "/var/lib/lighthouse/beacon/testnet/${config_dir}/bootstrap_nodes.txt")"
+  set +e
+  __network="--testnet-dir=/var/lib/lighthouse/beacon/testnet/${config_dir} --boot-nodes=${bootnodes} \
+--self-limiter=blob_sidecars_by_range:256/10"
+else
+  __network="--network=${NETWORK}"
+fi
+
 # Check whether we should rapid sync
 if [ -n "${RAPID_SYNC_URL}" ]; then
   __rapid_sync="--checkpoint-sync-url=${RAPID_SYNC_URL}"
@@ -58,4 +83,4 @@ fi
 
 # Word splitting is desired for the command line parameters
 # shellcheck disable=SC2086
-exec "$@" ${__mev_boost} ${__rapid_sync} ${__prune} ${__beacon_stats} ${__ipv6} ${CL_EXTRAS}
+exec "$@" ${__network} ${__mev_boost} ${__rapid_sync} ${__prune} ${__beacon_stats} ${__ipv6} ${CL_EXTRAS}
diff --git a/lodestar.yml b/lodestar.yml
index 0c191860..53323890 100644
--- a/lodestar.yml
+++ b/lodestar.yml
@@ -87,6 +87,7 @@ services:
       - GRAFFITI=${GRAFFITI:-}
       - DEFAULT_GRAFFITI=${DEFAULT_GRAFFITI:-false}
       - WEB3SIGNER=${WEB3SIGNER}
+      - NETWORK=${NETWORK}
     volumes:
       - lsvalidator-data:/var/lib/lodestar/validators
       - /etc/localtime:/etc/localtime:ro
@@ -120,8 +121,6 @@ services:
       - 0.0.0.0
       - --logLevel
       - ${LOG_LEVEL}
-      - --network
-      - ${NETWORK}
       - --suggestedFeeRecipient
       - ${FEE_RECIPIENT}
       - --force
diff --git a/lodestar/docker-entrypoint-vc.sh b/lodestar/docker-entrypoint-vc.sh
index cb1ecf79..b204b340 100755
--- a/lodestar/docker-entrypoint-vc.sh
+++ b/lodestar/docker-entrypoint-vc.sh
@@ -6,6 +6,29 @@ if [ "$(id -u)" = '0' ]; then
   exec su-exec lsvalidator docker-entrypoint.sh "$@"
 fi
 
+if [[ "${NETWORK}" =~ ^https?:// ]]; then
+  echo "Custom testnet at ${NETWORK}"
+  repo=$(awk -F'/tree/' '{print $1}' <<< "${NETWORK}")
+  branch=$(awk -F'/tree/' '{print $2}' <<< "${NETWORK}" | cut -d'/' -f1)
+  config_dir=$(awk -F'/tree/' '{print $2}' <<< "${NETWORK}" | cut -d'/' -f2-)
+  echo "This appears to be the ${repo} repo, branch ${branch} and config directory ${config_dir}."
+  # For want of something more amazing, let's just fail if git fails to pull this
+  set -e
+  if [ ! -d "/var/lib/lodestar/validators/testnet/${config_dir}" ]; then
+    mkdir -p /var/lib/lodestar/validators/testnet
+    cd /var/lib/lodestar/validators/testnet
+    git init --initial-branch="${branch}"
+    git remote add origin "${repo}"
+    git config core.sparseCheckout true
+    echo "${config_dir}" > .git/info/sparse-checkout
+    git pull origin "${branch}"
+  fi
+  set +e
+  __network="--paramsFile=/var/lib/lodestar/validators/testnet/${config_dir}/config.yaml"
+else
+  __network="--network ${NETWORK}"
+fi
+
 # Check whether we should use MEV Boost
 if [ "${MEV_BOOST}" = "true" ]; then
   __mev_boost="--builder"
@@ -40,9 +63,9 @@ fi
 if [ "${DEFAULT_GRAFFITI}" = "true" ]; then
 # Word splitting is desired for the command line parameters
 # shellcheck disable=SC2086
-  exec "$@" ${__mev_boost} ${__beacon_stats} ${__doppel} ${__w3s_url} ${VC_EXTRAS}
+  exec "$@" ${__network} ${__mev_boost} ${__beacon_stats} ${__doppel} ${__w3s_url} ${VC_EXTRAS}
 else
 # Word splitting is desired for the command line parameters
 # shellcheck disable=SC2086
-  exec "$@" "--graffiti" "${GRAFFITI}" ${__mev_boost} ${__beacon_stats} ${__doppel} ${__w3s_url} ${VC_EXTRAS}
+  exec "$@" ${__network} "--graffiti" "${GRAFFITI}" ${__mev_boost} ${__beacon_stats} ${__doppel} ${__w3s_url} ${VC_EXTRAS}
 fi
diff --git a/teku-vc-only.yml b/teku-vc-only.yml
index 1ee0d452..427e51c0 100644
--- a/teku-vc-only.yml
+++ b/teku-vc-only.yml
@@ -32,6 +32,7 @@ services:
       - GRAFFITI=${GRAFFITI:-}
       - DEFAULT_GRAFFITI=${DEFAULT_GRAFFITI:-false}
       - WEB3SIGNER=${WEB3SIGNER:-false}
+      - NETWORK=${NETWORK}
     networks:
       default:
         aliases:
@@ -44,7 +45,6 @@ services:
       - --beacon-node-api-endpoints=${CL_NODE:-http://consensus:5052}
       - --data-path=/var/lib/teku
       - --log-destination=CONSOLE
-      - --network=${NETWORK}
       - --validator-keys=/var/lib/teku/validator-keys:/var/lib/teku/validator-passwords
       - --validators-early-attestations-enabled=false
       - --validator-api-enabled=true
diff --git a/teku/docker-entrypoint-vc.sh b/teku/docker-entrypoint-vc.sh
index 301c7cf4..d8e22af1 100755
--- a/teku/docker-entrypoint-vc.sh
+++ b/teku/docker-entrypoint-vc.sh
@@ -5,6 +5,29 @@ if [ "$(id -u)" = '0' ]; then
   exec gosu teku docker-entrypoint.sh "$@"
 fi
 
+if [[ "${NETWORK}" =~ ^https?:// ]]; then
+  echo "Custom testnet at ${NETWORK}"
+  repo=$(awk -F'/tree/' '{print $1}' <<< "${NETWORK}")
+  branch=$(awk -F'/tree/' '{print $2}' <<< "${NETWORK}" | cut -d'/' -f1)
+  config_dir=$(awk -F'/tree/' '{print $2}' <<< "${NETWORK}" | cut -d'/' -f2-)
+  echo "This appears to be the ${repo} repo, branch ${branch} and config directory ${config_dir}."
+  # For want of something more amazing, let's just fail if git fails to pull this
+  set -e
+  if [ ! -d "/var/lib/teku/testnet/${config_dir}" ]; then
+    mkdir -p /var/lib/teku/testnet
+    cd /var/lib/teku/testnet
+    git init --initial-branch="${branch}"
+    git remote add origin "${repo}"
+    git config core.sparseCheckout true
+    echo "${config_dir}" > .git/info/sparse-checkout
+    git pull origin "${branch}"
+  fi
+  set +e
+  __network="--network=/var/lib/teku/testnet/${config_dir}/config.yaml"
+else
+  __network="--network=${NETWORK}"
+fi
+
 if [ -f /var/lib/teku/teku-keyapi.keystore ]; then
     if [ "$(date +%s -r /var/lib/teku/teku-keyapi.keystore)" -lt "$(date +%s --date="300 days ago")" ]; then
        rm /var/lib/teku/teku-keyapi.keystore
@@ -59,9 +82,9 @@ fi
 if [ "${DEFAULT_GRAFFITI}" = "true" ]; then
 # Word splitting is desired for the command line parameters
 # shellcheck disable=SC2086
-  exec "$@" ${__w3s_url} ${__mev_boost} ${__doppel} ${VC_EXTRAS}
+  exec "$@" ${__network} ${__w3s_url} ${__mev_boost} ${__doppel} ${VC_EXTRAS}
 else
 # Word splitting is desired for the command line parameters
 # shellcheck disable=SC2086
-  exec "$@" "--validators-graffiti=${GRAFFITI}" ${__w3s_url} ${__mev_boost} ${__doppel} ${VC_EXTRAS}
+  exec "$@" ${__network} "--validators-graffiti=${GRAFFITI}" ${__w3s_url} ${__mev_boost} ${__doppel} ${VC_EXTRAS}
 fi