diff --git a/velox/functions/lib/DateTimeFormatter.cpp b/velox/functions/lib/DateTimeFormatter.cpp
index a9df69d71f050..16f8b10aa9578 100644
--- a/velox/functions/lib/DateTimeFormatter.cpp
+++ b/velox/functions/lib/DateTimeFormatter.cpp
@@ -16,6 +16,10 @@
 
 #include "velox/functions/lib/DateTimeFormatter.h"
 #include <folly/String.h>
+#include <unicode/locid.h>
+#include <unicode/timezone.h>
+#include <unicode/tzfmt.h>
+#include <unicode/unistr.h>
 #include <charconv>
 #include <cstring>
 #include <stdexcept>
@@ -1173,10 +1177,10 @@ uint32_t DateTimeFormatter::maxResultSize(const tz::TimeZone* timezone) const {
           // https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
           size += 5;
         } else {
-          VELOX_NYI(
-              "Date format specifier is not yet implemented: {} ({})",
-              getSpecifierName(token.pattern.specifier),
-              token.pattern.minRepresentDigits);
+          // The longest time zone long name is 40, Australian Central Western
+          // Standard Time.
+          // https://www.timeanddate.com/time/zones/
+          size += 50;
         }
 
         break;
@@ -1430,8 +1434,33 @@ int32_t DateTimeFormatter::format(
             std::memcpy(result, abbrev.data(), abbrev.length());
             result += abbrev.length();
           } else {
-            // TODO: implement full name time zone
-            VELOX_NYI("full time zone name is not yet supported");
+            UErrorCode success = U_ZERO_ERROR;
+
+            static const icu::Locale locale("en", "US");
+            static const std::unique_ptr<icu::TimeZoneFormat> format(
+                icu::TimeZoneFormat::createInstance(locale, success));
+            VELOX_USER_CHECK_NOT_NULL(format);
+
+            // Get the ICU TimeZone by name
+            const std::string& timeZoneName = timezone->name();
+            std::unique_ptr<icu::TimeZone> tz(
+                icu::TimeZone::createTimeZone(icu::UnicodeString(
+                    timeZoneName.data(), timeZoneName.length())));
+            VELOX_USER_CHECK_NOT_NULL(tz);
+
+            // Format the time zone to get the long name.
+            icu::UnicodeString longName;
+            format->format(
+                UTimeZoneFormatStyle::UTZFMT_STYLE_SPECIFIC_LONG,
+                *tz,
+                (double)timestamp.getSeconds() * 1000.0, // ICU expects a double
+                longName);
+
+            // Convert the UnicodeString back to a string and write it out
+            std::string longNameStr;
+            longName.toUTF8String(longNameStr);
+            std::memcpy(result, longNameStr.data(), longNameStr.length());
+            result += longNameStr.length();
           }
         } break;
 
diff --git a/velox/functions/prestosql/tests/DateTimeFunctionsTest.cpp b/velox/functions/prestosql/tests/DateTimeFunctionsTest.cpp
index 661874dda3fbd..530c5fffa4bf3 100644
--- a/velox/functions/prestosql/tests/DateTimeFunctionsTest.cpp
+++ b/velox/functions/prestosql/tests/DateTimeFunctionsTest.cpp
@@ -3272,21 +3272,39 @@ TEST_F(DateTimeFunctionsTest, formatDateTime) {
   EXPECT_EQ("IST", formatDatetime(parseTimestamp("1970-01-01"), "zzz"));
   EXPECT_EQ("IST", formatDatetime(parseTimestamp("1970-01-01"), "zz"));
   EXPECT_EQ("IST", formatDatetime(parseTimestamp("1970-01-01"), "z"));
+  EXPECT_EQ(
+      "India Standard Time",
+      formatDatetime(parseTimestamp("1970-01-01"), "zzzz"));
+  EXPECT_EQ(
+      "India Standard Time",
+      formatDatetime(parseTimestamp("1970-01-01"), "zzzzzzzzzzzzzzzzzzzzzz"));
 
   // Test daylight savings.
   setQueryTimeZone("America/Los_Angeles");
   EXPECT_EQ("PST", formatDatetime(parseTimestamp("1970-01-01"), "z"));
   EXPECT_EQ("PDT", formatDatetime(parseTimestamp("1970-10-01"), "z"));
+  EXPECT_EQ(
+      "Pacific Standard Time",
+      formatDatetime(parseTimestamp("1970-01-01"), "zzzz"));
+  EXPECT_EQ(
+      "Pacific Daylight Time",
+      formatDatetime(parseTimestamp("1970-10-01"), "zzzz"));
 
   // Test a long abbreviation.
   setQueryTimeZone("Asia/Colombo");
   EXPECT_EQ("+0530", formatDatetime(parseTimestamp("1970-10-01"), "z"));
+  EXPECT_EQ(
+      "India Standard Time",
+      formatDatetime(parseTimestamp("1970-10-01"), "zzzz"));
 
-  setQueryTimeZone("Asia/Kolkata");
-  // We don't support more than 3 'z's yet.
-  EXPECT_THROW(
-      formatDatetime(parseTimestamp("1970-01-01"), "zzzz"), VeloxRuntimeError);
+  // Test a long long name.
+  setQueryTimeZone("Australia/Eucla");
+  EXPECT_EQ("+0845", formatDatetime(parseTimestamp("1970-10-01"), "z"));
+  EXPECT_EQ(
+      "Australian Central Western Standard Time",
+      formatDatetime(parseTimestamp("1970-10-01"), "zzzz"));
 
+  setQueryTimeZone("Asia/Kolkata");
   // Literal test cases.
   EXPECT_EQ("hello", formatDatetime(parseTimestamp("1970-01-01"), "'hello'"));
   EXPECT_EQ("'", formatDatetime(parseTimestamp("1970-01-01"), "''"));