diff --git a/src/Microsoft.PowerShell.Commands.Management/commands/management/Computer.cs b/src/Microsoft.PowerShell.Commands.Management/commands/management/Computer.cs
index 5d2513a47ae..023d1421434 100644
--- a/src/Microsoft.PowerShell.Commands.Management/commands/management/Computer.cs
+++ b/src/Microsoft.PowerShell.Commands.Management/commands/management/Computer.cs
@@ -1812,7 +1812,7 @@ internal static string GetLocalAdminUserName(string computerName, PSCredential p
                 }
                 else
                 {
-                    localUserName = computerName.Substring(0, dotIndex) + "\\" + psLocalCredential.UserName;
+                    localUserName = string.Concat(computerName.AsSpan().Slice(0, dotIndex), "\\", psLocalCredential.UserName);
                 }
             }
 
diff --git a/src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/Common/WebRequestPSCmdlet.Common.cs b/src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/Common/WebRequestPSCmdlet.Common.cs
index 94dde3c00fb..370438c872a 100644
--- a/src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/Common/WebRequestPSCmdlet.Common.cs
+++ b/src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/Common/WebRequestPSCmdlet.Common.cs
@@ -734,7 +734,7 @@ private Uri PrepareUri(Uri uri)
                 UriBuilder uriBuilder = new UriBuilder(uri);
                 if (uriBuilder.Query != null && uriBuilder.Query.Length > 1)
                 {
-                    uriBuilder.Query = uriBuilder.Query.Substring(1) + "&" + FormatDictionary(bodyAsDictionary);
+                    uriBuilder.Query = string.Concat(uriBuilder.Query.AsSpan().Slice(1), "&", FormatDictionary(bodyAsDictionary));
                 }
                 else
                 {
diff --git a/src/Microsoft.WSMan.Management/ConfigProvider.cs b/src/Microsoft.WSMan.Management/ConfigProvider.cs
index 326f53d4d94..d933a806c06 100644
--- a/src/Microsoft.WSMan.Management/ConfigProvider.cs
+++ b/src/Microsoft.WSMan.Management/ConfigProvider.cs
@@ -3647,13 +3647,13 @@ private string GetCorrectCaseOfName(string ChildName, string hostname, string pa
                 else
                 {
                     if (ChildName.StartsWith(WSManStringLiterals.containerListener, StringComparison.OrdinalIgnoreCase))
-                        result = WSManStringLiterals.containerListener + "_" + ChildName.Substring(ChildName.IndexOf('_') + 1);
+                        result = string.Concat(WSManStringLiterals.containerListener, "_", ChildName.AsSpan().Slice(ChildName.IndexOf('_') + 1));
                     if (ChildName.StartsWith(WSManStringLiterals.containerSingleResource, StringComparison.OrdinalIgnoreCase))
-                        result = WSManStringLiterals.containerSingleResource + "_" + ChildName.Substring(ChildName.IndexOf('_') + 1);
+                        result = string.Concat(WSManStringLiterals.containerSingleResource, "_", ChildName.AsSpan().Slice(ChildName.IndexOf('_') + 1));
                     if (ChildName.StartsWith(WSManStringLiterals.containerSecurity, StringComparison.OrdinalIgnoreCase))
-                        result = WSManStringLiterals.containerSecurity + "_" + ChildName.Substring(ChildName.IndexOf('_') + 1);
+                        result = string.Concat(WSManStringLiterals.containerSecurity, "_", ChildName.AsSpan().Slice(ChildName.IndexOf('_') + 1));
                     if (ChildName.StartsWith(WSManStringLiterals.containerClientCertificate, StringComparison.OrdinalIgnoreCase))
-                        result = WSManStringLiterals.containerClientCertificate + "_" + ChildName.Substring(ChildName.IndexOf('_') + 1);
+                        result = string.Concat(WSManStringLiterals.containerClientCertificate, "_", ChildName.AsSpan().Slice(ChildName.IndexOf('_') + 1));
                 }
             }
 
diff --git a/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs b/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs
index a3c5b2053ef..45677ea1734 100644
--- a/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs
+++ b/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs
@@ -511,7 +511,7 @@ internal static List<CompletionResult> CompleteCommandParameter(CompletionContex
                 && !string.IsNullOrWhiteSpace(context.WordToComplete) && context.WordToComplete.StartsWith('-'))
             {
                 var lastAst = context.RelatedAsts.Last();
-                var wordToMatch = context.WordToComplete.Substring(1) + "*";
+                var wordToMatch = string.Concat(context.WordToComplete.AsSpan().Slice(1), "*");
                 var pattern = WildcardPattern.Get(wordToMatch, WildcardOptions.IgnoreCase);
                 var parameterNames = keywordAst.CommandElements.Where(ast => ast is CommandParameterAst).Select(ast => (ast as CommandParameterAst).ParameterName);
                 foreach (var parameterName in s_parameterNamesOfImportDSCResource)
@@ -4708,7 +4708,7 @@ internal static List<CompletionResult> CompleteVariable(CompletionContext contex
                 provider = wordToComplete.Substring(0, colon + 1);
                 if (s_variableScopes.Contains(provider, StringComparer.OrdinalIgnoreCase))
                 {
-                    pattern = "variable:" + wordToComplete.Substring(colon + 1) + "*";
+                    pattern = string.Concat("variable:", wordToComplete.AsSpan().Slice(colon + 1), "*");
                 }
                 else
                 {
diff --git a/src/System.Management.Automation/engine/runtime/Operations/ArrayOps.cs b/src/System.Management.Automation/engine/runtime/Operations/ArrayOps.cs
index d340f8c2667..5ce3b857c31 100644
--- a/src/System.Management.Automation/engine/runtime/Operations/ArrayOps.cs
+++ b/src/System.Management.Automation/engine/runtime/Operations/ArrayOps.cs
@@ -231,7 +231,7 @@ internal static string IndexStringMessage(object index)
             // Convert this index into something printable (we hope)...
             string msgString = PSObject.ToString(null, index, ",", null, null, true, true);
             if (msgString.Length > 20)
-                msgString = msgString.Substring(0, 20) + " ...";
+                msgString = string.Concat(msgString.AsSpan().Slice(0, 20), " ...");
             return msgString;
         }
 
diff --git a/src/System.Management.Automation/engine/runtime/Operations/MiscOps.cs b/src/System.Management.Automation/engine/runtime/Operations/MiscOps.cs
index a8f58d9deea..36088bc4937 100644
--- a/src/System.Management.Automation/engine/runtime/Operations/MiscOps.cs
+++ b/src/System.Management.Automation/engine/runtime/Operations/MiscOps.cs
@@ -407,7 +407,7 @@ private static string GetParameterText(string parameterName)
             else
             {
                 string whitespaces = parameterName.Substring(endPosition);
-                parameterText = "-" + parameterName.Substring(0, endPosition) + ":" + whitespaces;
+                parameterText = string.Concat("-", parameterName.AsSpan().Slice(0, endPosition), ":", whitespaces);
             }
 
             return parameterText;