diff --git a/master_changes.md b/master_changes.md
index 428df6ddceb..2efe7e53f99 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -119,6 +119,7 @@ users)
   * download tool: Use fetch on DragonFlyBSD and ftp on NetBSD [#6305 @kit-ty-kate]
   * Prefer curl over any other download tools on every systems, if available [#6305 @kit-ty-kate]
   * Avoid issues when using wget2 where the requested url might return an html page instead of the expected content [#6303 @kit-ty-kate]
+  * Ensure each repositories stored in repos-config is associated with an URL [#6249 @kit-ty-kate]
 
 ## Internal: Windows
 
@@ -164,6 +165,7 @@ users)
 ## opam-format
   * `OpamFormula.string_of_relop`: export function [#6197 @mbarbin]
   * `OpamFormula.all_relop`: a list of all operators [#6197 @mbarbin]
+  * `OpamFile.Repos_config.t`: change the type to not allow repositories without an URL [#6249 @kit-ty-kate]
 
 ## opam-core
   * `OpamStd.Sys.{get_terminal_columns,uname,getconf,guess_shell_compat}`: Harden the process calls to account for failures [#6230 @kit-ty-kate - fix #6215]
diff --git a/src/client/opamClient.ml b/src/client/opamClient.ml
index 14db917ed22..2b37a6f6fcc 100644
--- a/src/client/opamClient.ml
+++ b/src/client/opamClient.ml
@@ -1890,10 +1890,7 @@ let init
           else config
         in
         OpamFile.Config.write config_f config;
-        let repos_config =
-          OpamRepositoryName.Map.of_list repos |>
-          OpamRepositoryName.Map.map OpamStd.Option.some
-        in
+        let repos_config = OpamRepositoryName.Map.of_list repos in
         OpamFile.Repos_config.write (OpamPath.repos_config root)
           repos_config;
 
diff --git a/src/format/opamFile.ml b/src/format/opamFile.ml
index 28707cc9658..1d94fa0a9b9 100644
--- a/src/format/opamFile.ml
+++ b/src/format/opamFile.ml
@@ -1798,7 +1798,7 @@ module InitConfigSyntax = struct
     Pp.V.map_options_3
       (Pp.V.string -|
        Pp.of_module "repository" (module OpamRepositoryName))
-      (Pp.opt @@ Pp.singleton -| Pp.V.url)
+      (Pp.singleton -| Pp.V.url)
       (Pp.map_list Pp.V.string)
       (Pp.opt @@
        Pp.singleton -| Pp.V.int -|
@@ -1821,10 +1821,8 @@ module InitConfigSyntax = struct
         with_repositories repositories
         (Pp.V.map_list ~depth:1 @@
          pp_repository_def -|
-         Pp.pp (fun ~pos -> function
-             | (name, Some url, ta) -> (name, (url, ta))
-             | (_, None, _) -> Pp.bad_format ~pos "Missing repository URL")
-           (fun (name, (url, ta)) -> (name, Some url, ta)));
+         Pp.pp (fun ~pos:_ (name, url, ta) -> (name, (url, ta)))
+           (fun (name, (url, ta)) -> (name, url, ta)));
       "default-compiler", Pp.ppacc
         with_default_compiler default_compiler
         (Pp.V.package_formula `Disj Pp.V.(constraints Pp.V.version));
@@ -1965,7 +1963,7 @@ module Repos_configSyntax = struct
   let format_version = OpamVersion.of_string "2.0"
   let file_format_version = OpamVersion.of_string "2.0"
 
-  type t = ((url * trust_anchors option) option) OpamRepositoryName.Map.t
+  type t = (url * trust_anchors option) OpamRepositoryName.Map.t
 
   let empty = OpamRepositoryName.Map.empty
 
@@ -1975,12 +1973,8 @@ module Repos_configSyntax = struct
       ((Pp.V.map_list ~depth:1 @@
         InitConfigSyntax.pp_repository_def -|
         Pp.pp
-          (fun ~pos:_ -> function
-             | (name, Some url, ta) -> name, Some (url, ta)
-             | (name, None, _) -> name, None)
-          (fun (name, def) -> match def with
-             | Some (url, ta) -> name, Some url, ta
-             | None -> name, None, None)) -|
+          (fun ~pos:_ (name, url, ta) -> (name, (url, ta)))
+          (fun (name, (url, ta)) -> (name, url, ta))) -|
        Pp.of_pair "repository-url-list"
          OpamRepositoryName.Map.(of_list, bindings));
   ]
diff --git a/src/format/opamFile.mli b/src/format/opamFile.mli
index 9ac19f15b87..45c51ef8320 100644
--- a/src/format/opamFile.mli
+++ b/src/format/opamFile.mli
@@ -1029,7 +1029,7 @@ module Repo_config_legacy : sig
 end
 
 module Repos_config: sig
-  type t = (url * trust_anchors option) option OpamRepositoryName.Map.t
+  type t = (url * trust_anchors option) OpamRepositoryName.Map.t
   include IO_FILE with type t := t
   module BestEffort: BestEffortRead with type t := t
 end
diff --git a/src/state/opamFormatUpgrade.ml b/src/state/opamFormatUpgrade.ml
index d2304e5c4f6..f488f661fb9 100644
--- a/src/state/opamFormatUpgrade.ml
+++ b/src/state/opamFormatUpgrade.ml
@@ -770,7 +770,7 @@ let from_1_3_dev7_to_2_0_alpha ~on_the_fly:_ root conf =
   in
   OpamFile.Repos_config.write (OpamPath.repos_config root)
     (OpamRepositoryName.Map.of_list
-       (List.map (fun (_, r, u) -> r, Some (u,None)) prio_repositories));
+       (List.map (fun (_, r, u) -> r, (u,None)) prio_repositories));
   let prio_repositories =
     List.stable_sort (fun (prio1, _, _) (prio2, _, _) -> prio2 - prio1)
       prio_repositories
diff --git a/src/state/opamRepositoryState.ml b/src/state/opamRepositoryState.ml
index bebc7d4e905..b7e8ff69a64 100644
--- a/src/state/opamRepositoryState.ml
+++ b/src/state/opamRepositoryState.ml
@@ -164,16 +164,11 @@ let load lock_kind gt =
          load with best-effort (read-only)"
       (OpamVersion.to_string (OpamFile.Config.opam_root_version gt.config))
       (OpamVersion.to_string (OpamFile.Config.root_version));
-  let mk_repo name url_opt = {
+  let mk_repo name (url, ta) = {
     repo_name = name;
-    repo_url = OpamStd.Option.Op.((url_opt >>| fst) +! OpamUrl.empty);
-    repo_trust = OpamStd.Option.Op.(url_opt >>= snd);
+    repo_url = url;
+    repo_trust = ta;
   } in
-  let uncached =
-    (* Don't cache repositories without remote, as they should be editable
-       in-place *)
-    OpamRepositoryName.Map.filter (fun _ url -> url = None) repos_map
-  in
   let repositories = OpamRepositoryName.Map.mapi mk_repo repos_map in
   let repos_tmp_root = lazy (OpamFilename.mk_tmp_dir ()) in
   let repos_tmp = Hashtbl.create 23 in
@@ -211,22 +206,8 @@ let load lock_kind gt =
     rt
   in
   match Cache.load gt.root with
-  | Some (repofiles, opams) when OpamRepositoryName.Map.is_empty uncached ->
-    log "Cache found";
-    make_rt repofiles opams
   | Some (repofiles, opams) ->
-    log "Cache found, loading repositories without remote only";
-    OpamFilename.with_flock_upgrade `Lock_read lock @@ fun _ ->
-    let repofiles, opams =
-      OpamRepositoryName.Map.fold (fun name url (defs, opams) ->
-          let repo = mk_repo name url in
-          let repo_def, repo_opams =
-            load_repo repo (get_root_raw gt.root repos_tmp name)
-          in
-          OpamRepositoryName.Map.add name repo_def defs,
-          OpamRepositoryName.Map.add name repo_opams opams)
-        uncached (repofiles, opams)
-    in
+    log "Cache found";
     make_rt repofiles opams
   | None ->
     log "No cache found";
@@ -297,7 +278,7 @@ let with_ lock gt f =
 
 let write_config rt =
   OpamFile.Repos_config.write (OpamPath.repos_config rt.repos_global.root)
-    (OpamRepositoryName.Map.map (fun r ->
+    (OpamRepositoryName.Map.filter_map (fun _ r ->
          if r.repo_url = OpamUrl.empty then None
          else Some (r.repo_url, r.repo_trust))
         rt.repositories)
@@ -312,4 +293,3 @@ let check_last_update () =
     OpamConsole.note "It seems you have not updated your repositories \
                       for a while. Consider updating them with:\n%s\n"
       (OpamConsole.colorise `bold "opam update");
-
diff --git a/tests/reftests/repository.test b/tests/reftests/repository.test
index 755d99f385c..d84dbba52ff 100644
--- a/tests/reftests/repository.test
+++ b/tests/reftests/repository.test
@@ -816,3 +816,55 @@ GARBAGE
 ### opam show two-three --raw
 [ERROR] No package matching two-three found
 # Return code 5 #
+### : Repo config with no url repo
+### opam switch create nourl --empty
+### opam repo remove --all repo versions
+### <nourl/repo>
+opam-version: "2.0"
+### <nourl/packages/no/no.1/opam>
+opam-version: "2.0"
+### cat OPAM/repo/repos-config
+opam-version: "2.0"
+### opam repo --all
+# Repository # Url # Switches(rank)
+### opam repo add nourl ./nourl --this-switch
+[nourl] Initialised
+### opam repo --all | grep -v '^#'
+nourl        file://${BASEDIR}/nourl nourl
+### opam list -A
+# Packages matching: any
+# Name # Installed # Synopsis
+no     --
+### <OPAM/repo/repos-config>
+opam-version: "2.0"
+repositories: [ "nourl" ]
+### opam repo --all
+[WARNING] Errors in ${BASEDIR}/OPAM/repo/repos-config, some fields have been ignored:
+            - At ${BASEDIR}/OPAM/repo/repos-config:2:16-2:23::
+              expected url
+
+# Repository # Url # Switches(rank)
+### <nourl/packages/yes/yes.1/opam>
+opam-version: "2.0"
+### opam update nourl
+[WARNING] Errors in ${BASEDIR}/OPAM/repo/repos-config, some fields have been ignored:
+            - At ${BASEDIR}/OPAM/repo/repos-config:2:16-2:23::
+              expected url
+
+[ERROR] Unknown repositories or installed packages: nourl
+# Return code 40 #
+### opam list -A
+[WARNING] Errors in ${BASEDIR}/OPAM/repo/repos-config, some fields have been ignored:
+            - At ${BASEDIR}/OPAM/repo/repos-config:2:16-2:23::
+              expected url
+
+# Packages matching: any
+# No matches found
+### sh -c "rm OPAM/repo/state-*.cache"
+### opam list -A
+[WARNING] Errors in ${BASEDIR}/OPAM/repo/repos-config, some fields have been ignored:
+            - At ${BASEDIR}/OPAM/repo/repos-config:2:16-2:23::
+              expected url
+
+# Packages matching: any
+# No matches found