diff --git a/ebos/eclgenericvanguard.cc b/ebos/eclgenericvanguard.cc
index 33bcbb3bb..149a551c2 100644
--- a/ebos/eclgenericvanguard.cc
+++ b/ebos/eclgenericvanguard.cc
@@ -25,7 +25,6 @@
 #include <ebos/eclgenericvanguard.hh>
 
 #include <opm/common/ErrorMacros.hpp>
-#include <opm/common/utility/FileSystem.hpp>
 #include <opm/common/utility/TimeService.hpp>
 #include <opm/parser/eclipse/Deck/Deck.hpp>
 #include <opm/parser/eclipse/EclipseState/Aquifer/NumericalAquifer/NumericalAquiferCell.hpp>
@@ -49,6 +48,7 @@
 #include <mpi.h>
 #endif // HAVE_MPI
 
+#include <filesystem>
 #include <stdexcept>
 
 namespace Opm {
@@ -144,18 +144,18 @@ void EclGenericVanguard::setExternalWTestState(std::unique_ptr<WellTestState> wt
 
 std::string EclGenericVanguard::canonicalDeckPath(const std::string& caseName)
 {
-    const auto fileExists = [](const filesystem::path& f) -> bool
+    const auto fileExists = [](const std::filesystem::path& f) -> bool
     {
-        if (!filesystem::exists(f))
+        if (!std::filesystem::exists(f))
             return false;
 
-        if (filesystem::is_regular_file(f))
+        if (std::filesystem::is_regular_file(f))
             return true;
 
-        return filesystem::is_symlink(f) && filesystem::is_regular_file(filesystem::read_symlink(f));
+        return std::filesystem::is_symlink(f) && std::filesystem::is_regular_file(std::filesystem::read_symlink(f));
     };
 
-    auto simcase = filesystem::path(caseName);
+    auto simcase = std::filesystem::path(caseName);
     if (fileExists(simcase))
         return simcase.string();
 
@@ -213,9 +213,9 @@ void EclGenericVanguard::updateOutputDir_(std::string outputDir,
         outputDir = ioConfig.getOutputDir();
 
     // ensure that the output directory exists and that it is a directory
-    if (!filesystem::is_directory(outputDir)) {
+    if (!std::filesystem::is_directory(outputDir)) {
         try {
-            filesystem::create_directories(outputDir);
+            std::filesystem::create_directories(outputDir);
         }
         catch (...) {
             throw std::runtime_error("Creation of output directory '"+outputDir+"' failed\n");
diff --git a/flow/flow_ebos_solvent.cpp b/flow/flow_ebos_solvent.cpp
index 0312c1841..cb40c9297 100644
--- a/flow/flow_ebos_solvent.cpp
+++ b/flow/flow_ebos_solvent.cpp
@@ -29,6 +29,8 @@
 #include <dune/common/parallel/mpihelper.hh>
 #endif
 
+#include <filesystem>
+
 namespace Opm {
 namespace Properties {
 namespace TTag {
diff --git a/opm/simulators/flow/FlowMainEbos.hpp b/opm/simulators/flow/FlowMainEbos.hpp
index 2430ee2ee..b3cc7ea43 100644
--- a/opm/simulators/flow/FlowMainEbos.hpp
+++ b/opm/simulators/flow/FlowMainEbos.hpp
@@ -37,6 +37,7 @@
 #include <opm/common/utility/String.hpp>
 
 #include <fmt/format.h>
+#include <filesystem>
 
 #if HAVE_DUNE_FEM
 #include <dune/fem/misc/mpimanager.hh>
@@ -466,7 +467,7 @@ namespace Opm
                 return;
             }
 
-            namespace fs = ::Opm::filesystem;
+            namespace fs = ::std::filesystem;
             const std::string& output_dir = eclState().getIOConfig().getOutputDir();
             fs::path output_path(output_dir);
             fs::path deck_filename(EWOMS_GET_PARAM(TypeTag, std::string, EclDeckFileName));
@@ -578,7 +579,7 @@ namespace Opm
                 report.reportFullyImplicit(ss);
                 OpmLog::info(ss.str());
                 const std::string dir = eclState().getIOConfig().getOutputDir();
-                namespace fs = ::Opm::filesystem;
+                namespace fs = ::std::filesystem;
                 fs::path output_dir(dir);
                 {
                     std::string filename = eclState().getIOConfig().getBaseName() + ".INFOSTEP";
diff --git a/opm/simulators/flow/Main.hpp b/opm/simulators/flow/Main.hpp
index a4b889b75..af3430b63 100644
--- a/opm/simulators/flow/Main.hpp
+++ b/opm/simulators/flow/Main.hpp
@@ -69,6 +69,7 @@
 
 #include <cassert>
 #include <cstdlib>
+#include <filesystem>
 #include <iostream>
 #include <memory>
 #include <stdexcept>
@@ -496,9 +497,9 @@ namespace Opm
             return true;
         }
 
-        filesystem::path simulationCaseName_(const std::string& casename)
+        std::filesystem::path simulationCaseName_(const std::string& casename)
         {
-            namespace fs = ::Opm::filesystem;
+            namespace fs = ::std::filesystem;
 
             auto exists = [](const fs::path& f)
             {
diff --git a/opm/simulators/linalg/WriteSystemMatrixHelper.hpp b/opm/simulators/linalg/WriteSystemMatrixHelper.hpp
index 35041dea4..496c3790b 100644
--- a/opm/simulators/linalg/WriteSystemMatrixHelper.hpp
+++ b/opm/simulators/linalg/WriteSystemMatrixHelper.hpp
@@ -23,6 +23,8 @@
 #include <dune/istl/matrixmarket.hh>
 #include <opm/simulators/linalg/MatrixMarketSpecializations.hpp>
 
+#include <filesystem>
+
 
 namespace Opm
 {
@@ -40,7 +42,7 @@ namespace Helper
         } else if (!dir.empty() && dir.back() != '/') {
             dir += "/";
         }
-        namespace fs = ::Opm::filesystem;
+        namespace fs = ::std::filesystem;
         fs::path output_dir(dir);
         fs::path subdir("reports");
         output_dir = output_dir / subdir;
diff --git a/opm/simulators/linalg/setupPropertyTree.cpp b/opm/simulators/linalg/setupPropertyTree.cpp
index b48df879f..5b4b8e7da 100644
--- a/opm/simulators/linalg/setupPropertyTree.cpp
+++ b/opm/simulators/linalg/setupPropertyTree.cpp
@@ -21,8 +21,7 @@
 
 #include <opm/simulators/linalg/setupPropertyTree.hpp>
 
-#include <opm/common/utility/FileSystem.hpp>
-
+#include <filesystem>
 #include <boost/version.hpp>
 
 namespace Opm
@@ -43,7 +42,7 @@ setupPropertyTree(FlowLinearSolverParameters p, // Note: copying the parameters
     // Get configuration from file.
     if (conf.size() > 5 && conf.substr(conf.size() - 5, 5) == ".json") { // the ends_with() method is not available until C++20
 #if BOOST_VERSION / 100 % 1000 > 48
-        if ( !filesystem::exists(conf) ) {
+        if ( !std::filesystem::exists(conf) ) {
             OPM_THROW(std::invalid_argument, "JSON file " << conf << " does not exist.");
         }
         try {
diff --git a/opm/simulators/utils/ParallelFileMerger.hpp b/opm/simulators/utils/ParallelFileMerger.hpp
index 4b6602ad8..5d8f91b84 100644
--- a/opm/simulators/utils/ParallelFileMerger.hpp
+++ b/opm/simulators/utils/ParallelFileMerger.hpp
@@ -21,20 +21,19 @@
 #ifndef OPM_PARALLELFILEMERGER_HEADER_INCLUDED
 #define OPM_PARALLELFILEMERGER_HEADER_INCLUDED
 
+#include <filesystem>
 #include <fstream>
 #include <memory>
 #include <regex>
 #include <string>
 
-#include <opm/common/utility/FileSystem.hpp>
-
 
 namespace Opm
 {
 namespace detail
 {
 
-namespace fs = ::Opm::filesystem;
+namespace fs = ::std::filesystem;
 
 /// \brief A functor that merges multiple files of a parallel run to one file.
 ///
diff --git a/opm/simulators/utils/readDeck.cpp b/opm/simulators/utils/readDeck.cpp
index 8cbe24ae7..d19139359 100644
--- a/opm/simulators/utils/readDeck.cpp
+++ b/opm/simulators/utils/readDeck.cpp
@@ -31,7 +31,6 @@
 #include <opm/common/ErrorMacros.hpp>
 #include <opm/common/OpmLog/EclipsePRTLog.hpp>
 #include <opm/common/OpmLog/OpmLog.hpp>
-#include <opm/common/utility/FileSystem.hpp>
 #include <opm/common/utility/OpmInputError.hpp>
 #include <opm/common/utility/String.hpp>
 
@@ -66,6 +65,7 @@
 
 #include <cstdlib>
 #include <cstdint>
+#include <filesystem>
 #include <functional>
 #include <memory>
 #include <sstream>
@@ -93,7 +93,7 @@ namespace {
 
     void ensureOutputDirExists_(const std::string& cmdline_output_dir)
     {
-        namespace fs = Opm::filesystem;
+        namespace fs = std::filesystem;
 
         if (! fs::is_directory(cmdline_output_dir)) {
             try {
@@ -350,7 +350,7 @@ Opm::setupLogging(const int          mpi_rank_,
     }
 
     // create logFile
-    using Opm::filesystem::path;
+    using std::filesystem::path;
     path fpath(deck_filename);
     std::string baseName;
     std::ostringstream debugFileStream;
@@ -369,7 +369,7 @@ Opm::setupLogging(const int          mpi_rank_,
     if (output_dir.empty()) {
         output_dir = fpath.has_parent_path()
             ? absolute(fpath.parent_path()).generic_string()
-            : Opm::filesystem::current_path().generic_string();
+            : std::filesystem::current_path().generic_string();
     }
 
     logFileStream << output_dir << "/" << baseName;
diff --git a/tests/test_vfpproperties.cpp b/tests/test_vfpproperties.cpp
index d1927b177..a2bb8cd53 100644
--- a/tests/test_vfpproperties.cpp
+++ b/tests/test_vfpproperties.cpp
@@ -23,6 +23,7 @@
 #define BOOST_TEST_MODULE VFPTest
 
 #include <algorithm>
+#include <filesystem>
 #include <memory>
 #include <map>
 #include <sstream>
@@ -645,7 +646,7 @@ BOOST_AUTO_TEST_CASE(ParseInterpolateRealisticVFPPROD)
     auto units = Opm::UnitSystem::newMETRIC();
 
     Opm::Parser parser;
-    Opm::filesystem::path file("VFPPROD2");
+    std::filesystem::path file("VFPPROD2");
 
     auto deck = parser.parseFile(file.string());