diff --git a/CHANGELOG.md b/CHANGELOG.md
index 66c39632..29984d2b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## [...]
 
+- Fix Crest::Resource#concat_urls [#229](https://github.com/mamantoha/crest/pull/229)
+
 ## [1.4.0][] (2024-08-26)
 
 - Fix typo in README.md by @kojix2 in [#223](https://github.com/mamantoha/crest/pull/223)
diff --git a/src/crest.cr b/src/crest.cr
index 0569729c..2816c4a9 100644
--- a/src/crest.cr
+++ b/src/crest.cr
@@ -8,7 +8,6 @@ require "./ext/io"
 require "./ext/int"
 require "./ext/float"
 require "./ext/http/cookie"
-require "./ext/uri"
 
 # This module's static methods are the entry point for using the Crest client.
 #
diff --git a/src/crest/resource.cr b/src/crest/resource.cr
index d9f9dc4d..9aed93ad 100644
--- a/src/crest/resource.cr
+++ b/src/crest/resource.cr
@@ -232,8 +232,11 @@ module Crest
       other
     end
 
-    private def concat_urls(url : String, suburl : String) : String
-      URI.join(url, URI.parse(suburl)).to_s
+    private def concat_urls(base_url : String, path : String) : String
+      base_url = base_url.ends_with?('/') ? base_url[...-1] : base_url
+      path = path.starts_with?('/') ? path[1..] : path
+
+      [base_url, path].join('/')
     end
   end
 end
diff --git a/src/ext/uri.cr b/src/ext/uri.cr
deleted file mode 100644
index 09b1be2c..00000000
--- a/src/ext/uri.cr
+++ /dev/null
@@ -1,14 +0,0 @@
-# :nodoc:
-# https://github.com/crystal-lang/crystal/issues/13114
-class URI
-  class BadURIError < Exception
-  end
-
-  def self.join(*args)
-    url = args[1..-1].reduce(URI.parse(args[0])) { |a, e| a.resolve(e) }
-
-    raise BadURIError.new("both URI are relative") if url.relative?
-
-    url
-  end
-end