diff --git a/.config/systemd/user/garmin-dump.service b/.config/systemd/user/garmin-dump.service
new file mode 100644
index 0000000..ab8db7f
--- /dev/null
+++ b/.config/systemd/user/garmin-dump.service
@@ -0,0 +1,11 @@
+[Unit]
+Description=Dump the Garmin database to ~/.local/share/negsplit/dumps
+StartLimitIntervalSec=2h
+StartLimitBurst=4
+
+[Service]
+Type=oneshot
+ExecStart=%h/.local/bin/garmin-dump
+# MariaDB not up yet (e.g. caught up right after boot)? retry a few times
+Restart=on-failure
+RestartSec=5min
diff --git a/.config/systemd/user/garmin-dump.timer b/.config/systemd/user/garmin-dump.timer
new file mode 100644
index 0000000..00bdbf1
--- /dev/null
+++ b/.config/systemd/user/garmin-dump.timer
@@ -0,0 +1,9 @@
+[Unit]
+Description=Dump the Garmin database weekly
+
+[Timer]
+OnCalendar=weekly
+Persistent=true
+
+[Install]
+WantedBy=timers.target
diff --git a/.github/README.md b/.github/README.md
index 071eb7c..fc46a7a 100644
--- a/.github/README.md
+++ b/.github/README.md
@@ -17,7 +17,7 @@ install script. This README lives in `.github/` to keep it out of the home direc
 | Audio / media | mpd, ncmpcpp, mpDris2, mpv, beets, pipewire |
 | Packaging | `.config/aurutils-makepkg.conf`, `.config/aurb/`, `.local/bin/aurb` / `aurs` (aurutils wrappers) |
 | Services | `.config/systemd/user/` (timers and overrides) |
-| Scripts | `.local/bin/` (screen layout, phone mount, video helpers, Library database dump) |
+| Scripts | `.local/bin/` (screen layout, phone mount, video helpers, Library and Garmin database dumps) |
 
 Note: `config.fish` sources `~/.bash_aliases`, so the aliases apply in both shells.
 
diff --git a/.local/bin/garmin-dump b/.local/bin/garmin-dump
new file mode 100755
index 0000000..a8bdee0
--- /dev/null
+++ b/.local/bin/garmin-dump
@@ -0,0 +1,24 @@
+#!/bin/bash
+# Dump the Garmin database to a per-ISO-week file, keeping the two newest weeks.
+set -euo pipefail
+
+cnf=${XDG_CONFIG_HOME:-$HOME/.config}/negsplit/dump.cnf
+dir=${XDG_DATA_HOME:-$HOME/.local/share}/negsplit/dumps
+out=$dir/Garmin-$(date +%G-W%V).sql.gz
+keep=2
+
+umask 077
+mkdir -p "$dir"
+
+# Write to a temporary file so a failed dump never replaces a good one
+tmp=$(mktemp "$dir/.dump.XXXXXX")
+trap 'rm -f "$tmp"' EXIT
+
+mariadb-dump --defaults-extra-file="$cnf" --single-transaction --databases Garmin | gzip > "$tmp"
+mv "$tmp" "$out"
+
+# Names sort by week, so all but the last $keep are the old ones
+dumps=("$dir"/Garmin-*.sql.gz)
+if (( ${#dumps[@]} > keep )); then
+    rm -f -- "${dumps[@]:0:${#dumps[@]}-keep}"
+fi