diff --git a/migrate.sh b/migrate.sh
new file mode 100755
index 0000000..181d4fe
--- /dev/null
+++ b/migrate.sh
@@ -0,0 +1,85 @@
+#!/bin/sh
+
+cd "$(dirname "$0")"
+prior_zed="$(pwd)/zed-v1.5.0"
+
+case $(uname -s) in
+    Darwin )
+        PATH=/Applications/Zui.app/Contents/Resources/app.asar.unpacked/zdeps:$PATH
+        src_dir="$HOME/Library/Application Support/Brim/lake"
+        dst_dir="$HOME/Library/Application Support/Zui/lake"
+        ;;
+    Linux )
+        PATH=/opt/Zui/resources/app.asar.unpacked/zdeps:$PATH
+        src_dir=$HOME/.config/Brim/lake
+        dst_dir=$HOME/.config/Zui/lake
+        ;;
+    * ) # Windows
+        PATH=$LOCALAPPDATA/Programs/Zui/resources/app.asar.unpacked/zdeps:$PATH
+        src_dir=$APPDATA/Brim/lake
+        dst_dir=$APPDATA/Zui/lake
+        ;;
+esac
+
+if [ $# -gt 2 ] || [ $# -eq 1 ]; then
+     echo "usage: $0 [SRC_DATA_DIR] [DST_DATA_DIR]" >&2
+     exit 1
+elif [ $# = 2 ]; then
+    src_dir=$1
+    dst_dir=$2
+fi
+
+set -e
+
+echo "migrating lake at '$src_dir' to '$dst_dir'"
+cd "$src_dir"
+
+# Sort these by decreasing modification time so we can use
+# 'entry.id==... | head 1 | yield entry.name' below to determine current
+# pool names.  (We can't use entry.ts for that because it reflects pool
+# creation time rather than modification time.)
+pools_zngs=$(ls -t pools/*.zng)
+
+if [ -e "$dst_dir" ]; then
+    if ! stderr=$(zed -lake "$dst_dir" ls 2>&1 >/dev/null); then
+        exec "fatal error: 'zed ls' failed with this output: '$stderr'" >&2
+        exit 1
+    fi
+else
+    zed init "$dst_dir"
+fi
+
+ksuid_glob='???????????????????????????'
+for pool_ksuid in $ksuid_glob; do
+    pool_name=$(zq -f text "entry.id==ksuid('$pool_ksuid') | head 1 | yield entry.name" $pools_zngs)
+
+    # join() is needed to deal with nested pool keys, e.g., kafka.offset
+    pool_order=$(zq -f text "entry.id==ksuid('$pool_ksuid') | head 1 | yield join(entry.layout.keys[0], '.') + ':' + entry.layout.order" $pools_zngs)
+
+    # Look for [0-9]*.zng so snap.zng is excluded
+    branch_count=$(zq -f text 'yield entry.name | sort | uniq | count()' $pool_ksuid/branches/[0-9]*.zng)
+    if [ "$branch_count" != 1 ]; then
+        # Not attempting to migrate pools with multiple branches yet
+        echo "skipping '$pool_name' ($pool_ksuid): found multiple ($branch_count) branches"
+        continue
+    fi
+
+    if zed -lake "$dst_dir" ls "$pool_name" >/dev/null 2>&1; then
+        echo "skipping '$pool_name' ($pool_ksuid): pool name already exists in '$dst_dir'"
+        continue
+    fi
+
+    echo "migrating pool '$pool_name' ($pool_ksuid)"
+    prior_zng=$(mktemp)
+    $prior_zed -lake "$src_dir" -use "$pool_name" query '*' > "$prior_zng"
+    zed -lake "$dst_dir" create -q -orderby "$pool_order" "$pool_name"
+    zed -lake "$dst_dir" load -q -use "$pool_name" "$prior_zng"
+    new_zng=$(mktemp)
+    zed -lake "$dst_dir" -use "$pool_name" query '*' > "$new_zng"
+    if ! cmp -s "$prior_zng" "$new_zng"; then
+        echo "error: contents of migrated pool '$pool_name' differ from original"
+        echo "pool dump before/after: $prior_zng $new_zng"
+    else
+        rm -f "$prior_zng" "$new_zng"
+    fi
+done