diff --git a/assets/package-lock.json b/assets/package-lock.json
index f2f110112e..a1b32a05cc 100644
--- a/assets/package-lock.json
+++ b/assets/package-lock.json
@@ -18,7 +18,7 @@
         "jsts": "^2.11.0",
         "lit-html": "^3.1.1",
         "ol": "^10.2.1",
-        "proj4": "^2.11.0",
+        "proj4rs": "^0.1.6",
         "shpjs": "^6.1.0",
         "svg-sprite-loader": "^6.0.11",
         "svgo": "^3.2.0",
@@ -4003,6 +4003,12 @@
         "wkt-parser": "^1.3.3"
       }
     },
+    "node_modules/proj4rs": {
+      "version": "0.1.6",
+      "resolved": "https://registry.npmjs.org/proj4rs/-/proj4rs-0.1.6.tgz",
+      "integrity": "sha512-EiDgeoJFfoJ/NxkjCgLde0ZsEZHSx8myFHjYcgCroAx7LeITdWpTjTrhK4Obm05CBzT1IVX8U7cV8aPVw5sPDw==",
+      "dev": true
+    },
     "node_modules/protocol-buffers-schema": {
       "version": "3.6.0",
       "resolved": "https://registry.npmjs.org/protocol-buffers-schema/-/protocol-buffers-schema-3.6.0.tgz",
diff --git a/assets/package.json b/assets/package.json
index 3eb2a7fca6..14cac38d39 100644
--- a/assets/package.json
+++ b/assets/package.json
@@ -16,7 +16,7 @@
     "jsts": "^2.11.0",
     "lit-html": "^3.1.1",
     "ol": "^10.2.1",
-    "proj4": "^2.11.0",
+    "proj4rs": "^0.1.6",
     "shpjs": "^6.1.0",
     "svg-sprite-loader": "^6.0.11",
     "svgo": "^3.2.0",
diff --git a/assets/src/index.js b/assets/src/index.js
index 3cf05cf566..000278b425 100644
--- a/assets/src/index.js
+++ b/assets/src/index.js
@@ -32,7 +32,7 @@ import executeJSFromServer from './modules/ExecuteJSFromServer.js';
 
 import olDep from './dependencies/ol.js';
 import litHTMLDep from './dependencies/lit-html.js';
-import proj4 from 'proj4';
+import {proj4} from 'proj4rs/proj4.js'
 
 lizMap.ol = olDep;
 lizMap.litHTML = litHTMLDep;
diff --git a/assets/src/modules/Lizmap.js b/assets/src/modules/Lizmap.js
index aca503cf04..06759e8423 100644
--- a/assets/src/modules/Lizmap.js
+++ b/assets/src/modules/Lizmap.js
@@ -33,7 +33,7 @@ import { Extent as olExtent, intersects as olExtentIntersects} from 'ol/extent.j
 import { Projection as olProjection, transform as olTransform, transformExtent as olTransformExtent, get as getProjection, clearAllProjections, addCommon } from 'ol/proj.js';
 import { register } from 'ol/proj/proj4.js';
 
-import proj4 from 'proj4';
+import {proj4} from 'proj4rs/proj4.js';
 import ProxyEvents from './ProxyEvents.js';
 
 /**