diff --git a/src/AIModel/AIBase.cxx b/src/AIModel/AIBase.cxx
index 9271f2fc9..e0fb4f256 100644
--- a/src/AIModel/AIBase.cxx
+++ b/src/AIModel/AIBase.cxx
@@ -544,7 +544,7 @@ std::vector<std::string> FGAIBase::resolveModelPath(ModelSearchOrder searchOrder
         for (SGPath p : globals->get_data_paths("AI")) {
             p.append(model_path);
             if (p.exists()) {
-                SG_LOG(SG_AI, SG_DEBUG, "Found AI model: " << p.local8BitStr());
+                SG_LOG(SG_AI, SG_DEBUG, "Found AI model: " << p);
                 path_list.push_back(p.local8BitStr());
                 break;
             }
diff --git a/src/Canvas/FGCanvasSystemAdapter.cxx b/src/Canvas/FGCanvasSystemAdapter.cxx
index bacb73d97..7743b020e 100644
--- a/src/Canvas/FGCanvasSystemAdapter.cxx
+++ b/src/Canvas/FGCanvasSystemAdapter.cxx
@@ -52,7 +52,7 @@ namespace canvas
       "canvas::Text: using font file " << path
     );
 
-    simgear::canvas::FontPtr font = osgText::readFontFile(path.local8BitStr());
+    simgear::canvas::FontPtr font = osgText::readFontFile(path.utf8Str());
     if( !font )
       SG_LOG
       (
@@ -86,9 +86,9 @@ namespace canvas
       SGPath valid_path = fgValidatePath(p, false);
       if( !valid_path.isNull() )
 #if OSG_VERSION_LESS_THAN(3,4,0)
-          return osgDB::readRefImageFile(valid_path.local8BitStr());
+          return osgDB::readRefImageFile(valid_path.utf8Str());
 #else
-          return osgDB::readRefImageFile(valid_path.local8BitStr());
+          return osgDB::readRefImageFile(valid_path.utf8Str());
 #endif
 
       SG_LOG(SG_IO, SG_ALERT, "canvas::Image: reading '" << path << "' denied");
@@ -98,9 +98,9 @@ namespace canvas
       SGPath tpath = globals->resolve_resource_path(path);
       if( !tpath.isNull() )
 #if OSG_VERSION_LESS_THAN(3,4,0)
-          return osgDB::readImageFile(tpath.local8BitStr());
+          return osgDB::readImageFile(tpath.utf8Str());
 #else
-          return osgDB::readRefImageFile(tpath.local8BitStr());
+          return osgDB::readRefImageFile(tpath.utf8Str());
 #endif
 
       SG_LOG(SG_IO, SG_ALERT, "canvas::Image: No such image: '" << path << "'");
diff --git a/src/Cockpit/NavDisplay.cxx b/src/Cockpit/NavDisplay.cxx
index bfabb9065..9885d81ff 100644
--- a/src/Cockpit/NavDisplay.cxx
+++ b/src/Cockpit/NavDisplay.cxx
@@ -777,7 +777,7 @@ NavDisplay::updateFont()
     }
 
     osg::ref_ptr<osgDB::ReaderWriter::Options> fontOptions = new osgDB::ReaderWriter::Options("monochrome");
-    osg::ref_ptr<osgText::Font> font = osgText::readFontFile(tpath.local8BitStr(), fontOptions.get());
+    osg::ref_ptr<osgText::Font> font = osgText::readFontFile(tpath.utf8Str(), fontOptions.get());
 
     if (font != 0) {
         _font = font;
diff --git a/src/Cockpit/wxradar.cxx b/src/Cockpit/wxradar.cxx
index 1165d93de..61a1b49bd 100644
--- a/src/Cockpit/wxradar.cxx
+++ b/src/Cockpit/wxradar.cxx
@@ -1084,7 +1084,7 @@ wxRadarBg::updateFont()
     }
     
     osg::ref_ptr<osgDB::ReaderWriter::Options> fontOptions = new osgDB::ReaderWriter::Options("monochrome");
-    osg::ref_ptr<osgText::Font> font = osgText::readFontFile(tpath.local8BitStr(), fontOptions.get());
+    osg::ref_ptr<osgText::Font> font = osgText::readFontFile(tpath.utf8Str(), fontOptions.get());
 
     if (font != 0) {
         _font = font;
diff --git a/src/Environment/ephemeris.cxx b/src/Environment/ephemeris.cxx
index db9d59b1e..046e50084 100644
--- a/src/Environment/ephemeris.cxx
+++ b/src/Environment/ephemeris.cxx
@@ -54,7 +54,7 @@ void Ephemeris::init()
 {
   SGPath ephem_data_path(globals->get_fg_root());
   ephem_data_path.append("Astro");
-  _impl.reset(new SGEphemeris(ephem_data_path.local8BitStr()));
+  _impl.reset(new SGEphemeris(ephem_data_path));
 
   tieStar("/ephemeris/sun/xs", _impl->get_sun(), &Star::getxs);
   tieStar("/ephemeris/sun/ys", _impl->get_sun(), &Star::getys);
diff --git a/src/GUI/AddonsModel.cxx b/src/GUI/AddonsModel.cxx
index 1d605051d..ba4ee041f 100644
--- a/src/GUI/AddonsModel.cxx
+++ b/src/GUI/AddonsModel.cxx
@@ -37,7 +37,7 @@ AddonsModel::AddonsModel(QObject* pr) :
     int roleValue = IdRole;
 
     for (auto it = m_roles.begin(); it != m_roles.end(); ++it) {
-        QByteArray name = (*it).toLocal8Bit();
+        QByteArray name = it->toUtf8();
         m_roleToName[roleValue] = name;
         m_nameToRole[*it] = roleValue++;
     }
diff --git a/src/GUI/FGFontCache.cxx b/src/GUI/FGFontCache.cxx
index fda16272b..6c6b02d20 100644
--- a/src/GUI/FGFontCache.cxx
+++ b/src/GUI/FGFontCache.cxx
@@ -27,6 +27,7 @@
 #include <plib/pu.h>
 
 #include <simgear/props/props.hxx>
+#include <simgear/misc/sg_dir.hxx>
 
 #include <Main/globals.hxx>
 
@@ -211,26 +212,19 @@ FGFontCache::getfntpath(const std::string& name)
 
 bool FGFontCache::initializeFonts()
 {
-    static std::string fontext("txf");
+    static std::string fontext(",txf");
     init();
-    std::string fontPath = _path.local8BitStr();
-    ulDir* fontdir = ulOpenDir(fontPath.c_str());
-    if (!fontdir)
-        return false;
-    const ulDirEnt *dirEntry;
-    while ((dirEntry = ulReadDir(fontdir)) != 0) {
-        SGPath path(_path);
-        path.append(dirEntry->d_name);
-        if (path.extension() == fontext) {
-            fntTexFont* f = new fntTexFont;
-            std::string ps = path.local8BitStr();
-            if (f->load(ps.c_str()))
-                _texFonts[std::string(dirEntry->d_name)] = f;
-            else
-                delete f;
-        }
+
+    auto dir = simgear::Dir(_path);
+    for (auto p : dir.children(simgear::Dir::TYPE_FILE, fontext)) {
+        fntTexFont* f = new fntTexFont;
+        // FIXME : this will fail when fonts are on UTF8 paths
+        if (f->load(p.local8BitStr()))
+            _texFonts[p.file()] = f;
+        else
+            delete f;
     }
-    ulCloseDir(fontdir);
+
     return true;
 }
 
diff --git a/src/Main/fg_init.cxx b/src/Main/fg_init.cxx
index cfdda7660..2ff531d71 100644
--- a/src/Main/fg_init.cxx
+++ b/src/Main/fg_init.cxx
@@ -483,7 +483,7 @@ bool fgInitHome()
     }
 
     char buf[16];
-    std::string ps = pidPath.local8BitStr();
+    std::string ps = pidPath.utf8Str();
 
     // do open+unlink trick to the file is deleted on exit, even if we
     // crash or exit(-1)
@@ -873,8 +873,7 @@ void fgCreateSubsystems(bool duringReset) {
 
     SGPath mpath( globals->get_fg_root() );
     mpath.append( fgGetString("/sim/rendering/materials-file") );
-    if ( ! globals->get_matlib()->load(globals->get_fg_root().local8BitStr(), mpath.local8BitStr(),
-            globals->get_props()) ) {
+    if ( ! globals->get_matlib()->load(globals->get_fg_root(), mpath, globals->get_props()) ) {
        throw sg_io_exception("Error loading materials file", mpath);
     }
 
diff --git a/src/Main/globals.cxx b/src/Main/globals.cxx
index bb9b5d9f4..1d5025b47 100644
--- a/src/Main/globals.cxx
+++ b/src/Main/globals.cxx
@@ -364,9 +364,7 @@ void FGGlobals::append_fg_scenery (const SGPath &path)
 
     // tell the ResouceManager about the scenery path
     // needed to load Models from this scenery path
-    simgear::ResourceManager::instance()->addBasePath(abspath.local8BitStr(),
-                                                      simgear::ResourceManager::PRIORITY_DEFAULT);
-    simgear::Dir dir(abspath);
+    simgear::ResourceManager::instance()->addBasePath(abspath, simgear::ResourceManager::PRIORITY_DEFAULT);
 
     fg_scenery.push_back(abspath);
     extra_read_allowed_paths.push_back(abspath);
diff --git a/src/Navaids/SHPParser.cxx b/src/Navaids/SHPParser.cxx
index 2d31bf237..58f597760 100644
--- a/src/Navaids/SHPParser.cxx
+++ b/src/Navaids/SHPParser.cxx
@@ -91,8 +91,13 @@ namespace flightgear
 void SHPParser::parsePolyLines(const SGPath& aPath, PolyLine::Type aTy,
                                PolyLineList& aResult, bool aClosed)
 {
-    std::string s = aPath.local8BitStr();
+#if defined(SG_WINDOWS)
+	const auto ws = aPath.wstr();
+	gzFile file = gzopen_w(ws.c_str(), "rb");
+#else
+    const auto s = aPath.utf8Str();
     gzFile file = gzopen(s.c_str(), "rb");
+#endif
     if (!file) {
         throw sg_io_exception("couldn't open file:", aPath);
     }
diff --git a/src/Scenery/tilemgr.cxx b/src/Scenery/tilemgr.cxx
index 9eb762044..e6049a613 100644
--- a/src/Scenery/tilemgr.cxx
+++ b/src/Scenery/tilemgr.cxx
@@ -172,10 +172,10 @@ void FGTileMgr::reinit()
     for (it = sc.begin(); it != sc.end(); ++it) {
         fp.push_back(it->local8BitStr());
     }
-    _options->setPluginStringData("SimGear::FG_ROOT", globals->get_fg_root().local8BitStr());
+    _options->setPluginStringData("SimGear::FG_ROOT", globals->get_fg_root().utf8Str());
     
     if (_terra_sync) {
-      _options->setPluginStringData("SimGear::TERRASYNC_ROOT", globals->get_terrasync_dir().local8BitStr());
+      _options->setPluginStringData("SimGear::TERRASYNC_ROOT", globals->get_terrasync_dir().utf8Str());
     }
     
     if (!_disableNasalHooks->getBoolValue())
diff --git a/src/Time/TimeManager.cxx b/src/Time/TimeManager.cxx
index c00bab291..1f6325cb0 100644
--- a/src/Time/TimeManager.cxx
+++ b/src/Time/TimeManager.cxx
@@ -386,9 +386,7 @@ void TimeManager::throttleUpdateRate()
 // periodic time updater wrapper
 void TimeManager::updateLocalTime() 
 {
-  SGPath zone(globals->get_fg_root());
-  zone.append("Timezone");
-  _impl->updateLocal(globals->get_aircraft_position(), zone.local8BitStr());
+  _impl->updateLocal(globals->get_aircraft_position(), globals->get_fg_root() / "Timezone");
 }
 
 void TimeManager::initTimeOffset()